WorldWideScience

Sample records for anti-prl cellulose particles

  1. Reactive Liftoff of Crystalline Cellulose Particles.

    Science.gov (United States)

    Teixeira, Andrew R; Krumm, Christoph; Vinter, Katherine P; Paulsen, Alex D; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D; Fan, Wei; Rothstein, Jonathan P; Dauenhauer, Paul J

    2015-06-09

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  2. Reactive Liftoff of Crystalline Cellulose Particles

    Science.gov (United States)

    Teixeira, Andrew R.; Krumm, Christoph; Vinter, Katherine P.; Paulsen, Alex D.; Zhu, Cheng; Maduskar, Saurabh; Joseph, Kristeen E.; Greco, Katharine; Stelatto, Michael; Davis, Eric; Vincent, Brendon; Hermann, Richard; Suszynski, Wieslaw; Schmidt, Lanny D.; Fan, Wei; Rothstein, Jonathan P.; Dauenhauer, Paul J.

    2015-06-01

    The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500-600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.

  3. Inclusion of solid particles in bacterial cellulose.

    Science.gov (United States)

    Serafica, G; Mormino, R; Bungay, H

    2002-05-01

    Depending upon the strain and the method of cultivation, bacterial cellulose can be reticulated filaments, pellets, or a dense, tough gel called a pellicle. The pellicular form is commonly made by surface culture, but a rotating disk bioreactor is more efficient and reduces the time of a run to about 3.5 days instead of the usual 12-20 days. Particles added to the medium as the gel is forming are trapped to form a new class of composite materials. Particles enter the films that are forming on the disks at rates depending on the size and geometry of the particle, as well as the rotational speed and concentration of the suspension.

  4. Dual morphology (fibres and particles) cellulosic filler for WPC materials

    Science.gov (United States)

    Valente, Marco; Tirillò, Jacopo; Quitadamo, Alessia; Santulli, Carlo

    2016-05-01

    Wood-plastic composites (WPC) were fabricated by using a polyethylene (PE) matrix and filling it with wood flour in the amount of 30 wt.%, and compared with the same composites with further amount of 10 wt.% of cellulosic recycled fibres added. The materials were produced by turbomixing and subsequent moulding under pressure. Mechanical properties of both WPC and WPC with cellulosic recycled fibres were evaluated through mechanical and physical-chemical tests. Tensile tests clarified that a moderate reduction is strength is observed with the bare introduction of wood flour with respect to the neat PE matrix, whilst some recovery is offered by the addition of recycled cellulose fibres. Even more promisingly, the elastic modulus of PE matrix is substantially improved by the addition of wood flour (around 8% on average) and much more so with the further addition of recycled cellulose (around 20% on average). The fracture surfaces from the tensile test were analysed by scanning electron microscope (SEM) indicating a reduction in microporosity as an effect of added cellulose. The water absorption test and the hardness measure (Shore D) were also performed. SEM analysis underlined the weak interface between both wood particle and cellulosic recycled fibres and matrix. The water absorption test showed a higher mass variation for pure WPC than WPC with cellulosic recycled fibres. The hardness measurement showed that the presence of cellulosic recycled fibres improves both superficial hardness of the composite and temperature resistance.

  5. Interrelationships between cellulase activity and cellulose particle morphology

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Johan P.; Donohoe, Bryon S.; Borch, Kim; Westh, Peter; Resch, Michael G.

    2016-06-11

    It is well documented that the enzymatic hydrolysis of cellulose follows a reaction pattern where an initial phase of relatively high activity is followed by a gradual slow-down over the entire course of the reaction. This phenomenon is not readily explained by conventional factors like substrate depletion, product inhibition or enzyme instability. It has been suggested that the underlying reason for the loss of enzyme activity is connected to the heterogeneous structure of cellulose, but so far attempts to establish quantitative measures of such a correlation remain speculative. Here, we have carried out an extensive microscopy study of Avicel particles during extended hydrolysis with Hypocrea jecorina cellobiohydrolase 1 (CBH1) and endoglucanase 1 and 3 (EG1 and EG3) alone and in mixtures. We have used differential interference contrast microscopy and transmission electron microscopy to observe and quantify structural features at um and nm resolution, respectively. We implemented a semi-automatic image analysis protocol, which allowed us to analyze almost 3000 individual micrographs comprising a total of more than 300,000 particles. From this analysis we estimated the temporal development of the accessible surface area throughout the reaction. We found that the number of particles and their size as well as the surface roughness contributed to surface area, and that within the investigated degree of conversion (<30 %) this measure correlated linearly with the rate of reaction. Based on this observation we argue that cellulose structure, specifically surface area and roughness, plays a major role in the ubiquitous rate loss observed for cellulases.

  6. Magnetic poly(lactide-co-glycolide) (PLGA) and cellulose particles for MRI-based cell tracking

    Science.gov (United States)

    Nkansah, Michael K.; Thakral, Durga; Shapiro, Erik M.

    2010-01-01

    Biodegradable, superparamagnetic micro- and nanoparticles of poly(lactide-co-glycolide) (PLGA) and cellulose were designed, fabricated and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into micro- and nanoparticles of PLGA and cellulose with high efficiency using an oil-in-water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt% for PLGA and 69.6 wt% for cellulose). While PLGA and cellulose nanoparticles displayed highest r2* values per millimole of iron (399 s-1mM-1 for cellulose and 505 s-1mM-1 for PLGA), micron-sized PLGA particles had a much higher r2* per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r2* molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r2* molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for non-invasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA-based particles) or long term (cellulose-based particles) experiments. PMID:21404328

  7. Magnetic poly(lactide-co-glycolide) and cellulose particles for MRI-based cell tracking.

    Science.gov (United States)

    Nkansah, Michael K; Thakral, Durga; Shapiro, Erik M

    2011-06-01

    Biodegradable, superparamagnetic microparticles and nanoparticles of poly(lactide-co-glycolide) (PLGA) and cellulose were designed, fabricated, and characterized for magnetic cell labeling. Monodisperse nanocrystals of magnetite were incorporated into microparticles and nanoparticles of PLGA and cellulose with high efficiency using an oil-in-water single emulsion technique. Superparamagnetic cores had high magnetization (72.1 emu/g). The resulting polymeric particles had smooth surface morphology and high magnetite content (43.3 wt % for PLGA and 69.6 wt % for cellulose). While PLGA and cellulose nanoparticles displayed highest r 2* values per millimole of iron (399 sec(-1) mM(-1) for cellulose and 505 sec(-1) mM(-1) for PLGA), micron-sized PLGA particles had a much higher r 2* per particle than either. After incubation for a month in citrate buffer (pH 5.5), magnetic PLGA particles lost close to 50% of their initial r 2* molar relaxivity, while magnetic cellulose particles remained intact, preserving over 85% of their initial r 2* molar relaxivity. Lastly, mesenchymal stem cells and human breast adenocarcinoma cells were magnetically labeled using these particles with no detectable cytotoxicity. These particles are ideally suited for noninvasive cell tracking in vivo via MRI and due to their vastly different degradation properties, offer unique potential for dedicated use for either short (PLGA-based particles) or long-term (cellulose-based particles) experiments.

  8. LEVOGLUCOSAN, A TRACER FOR CELLULOSE IN BIOMASS BURNING AND ATMOSPHERIC PARTICLES. (R823990)

    Science.gov (United States)

    AbstractThe major organic components of smoke particles from biomass burning are monosaccharide derivatives from the breakdown of cellulose, accompanied by generally lesser amounts of straight-chain, aliphatic and oxygenated compounds and terpenoids from vegetation wa...

  9. Interrelationships between cellulase activity and cellulose particle morphology

    DEFF Research Database (Denmark)

    Olsen, Johan Pelck; Donohoe, Bryon S.; Borch, Kim;

    2016-01-01

    It is well documented that the enzymatic hydrolysis of cellulose follows a reaction pattern where an initial phase of relatively high activity is followed by a gradual slow-down over the entire course of the reaction. This phenomenon is not readily explained by conventional factors like substrate...... depletion, product inhibition or enzyme instability. It has been suggested that the underlying reason for the loss of enzyme activity is connected to the heterogeneous structure of cellulose, but so far attempts to establish quantitative measures of such a correlation remain speculative. Here, we have...... on this observation we argue that cellulose structure, specifically surface area and roughness, plays a major role in the ubiquitous rate loss observed for cellulases....

  10. Bond scission cross sections for alpha-particles in cellulose nitrate (LR115)

    CERN Document Server

    Barillon, R; Chambaudet, A; Katz, R; Stoquert, J P; Pape, A

    1999-01-01

    Chemical damage created by alpha-particles in cellulose nitrate (LR115) have been studied by infrared spectroscopy. This technique enables identifying the sensitive bonds and giving an order of magnitude of their scission cross sections for given alpha-particle energies. The high cross sections observed suggest a new description of the track etch velocity in this material.

  11. EFFECTS OF ULTRASOUND ON THE MORPHOLOGY, PARTICLE SIZE, CRYSTALLINITY, AND CRYSTALLITE SIZE OF CELLULOSE

    Directory of Open Access Journals (Sweden)

    SUMARI SUMARI

    2014-05-01

    Full Text Available The aim of this study is to optimize ultrasound treatment to produce fragment of cellulose that is low in particles size, crystallite size, and crystallinity. Slurry of 1 % (w/v the cellulose was sonicated at different time periods and temperatures. An ultrasonic reactor was operated at 300 Watts and 28 kHz to cut down the polymer into smaller particles. We proved that ultrasound damages and fragments the cellulose particles into shorter fibers. The fiber lengths were reduced from in the range of 80-120 µm to 30-50 µm due to an hour ultrasonication and became 20-30 µm after 5 hours. It was also found some signs of erosion on the surface and stringy. The acoustic cavitation also generated a decrease in particle size, crystallinity, and crystallite size of the cellulose along with increasing sonication time but it did not change d-spacing. However, the highest reduction of particle size, crystallite size, and crystallinity of the cellulose occurred within the first hour of ultrasonication, after which the efficiency was decreased. The particle diameter, crystallite size, and crystallinity were decreased from 19.88 µm to 15.96 µm, 5.81 Å to 2.98 Å, and 77.7% to 73.9% respectively due to an hour ultrasound treatment at 40 °C. The treatment that was conducted at 40 °C or 60 °C did not give a different effect significantly. Cellulose with a smaller particle and crystallite size as well as a more amorphous shape is preferred for further study.

  12. Comparison of Influenza Virus Particle Purification Using Magnetic Sulfated Cellulose Particles with an Established Centrifugation Method for Analytics.

    Science.gov (United States)

    Serve, Anja; Pieler, Michael Martin; Benndorf, Dirk; Rapp, Erdmann; Wolff, Michael Werner; Reichl, Udo

    2015-11-03

    A method for the purification of influenza virus particles using novel magnetic sulfated cellulose particles is presented and compared to an established centrifugation method for analytics. Therefore, purified influenza A virus particles from adherent and suspension MDCK host cell lines were characterized on the protein level with mass spectrometry to compare the viral and residual host cell proteins. Both methods allowed one to identify all 10 influenza A virus proteins, including low-abundance proteins like the matrix protein 2 and nonstructural protein 1, with a similar impurity level of host cell proteins. Compared to the centrifugation method, use of the novel magnetic sulfated cellulose particles reduced the influenza A virus particle purification time from 3.5 h to 30 min before mass spectrometry analysis.

  13. Preparation and Application as the Filler for Elastomers of Flake-Shaped Cellulose Particles and Nanofibers

    Science.gov (United States)

    Nagatani, Asahiro; Lee, Seung-Hwan; Endo, Takashi; Tanaka, Tatsuya

    Fibrous cellulose made from wood pulp was mechanically milled into flake-shaped cellulose particles(FS-CPs) using a planetary ball mill with additives under several conditions. The average particle diameter of the FS-CPs was ca. 15μm, and the particles were available in a variety of thicknesses by changing the kind of the additives used in the milling process. FS-CPs-reinforced olefinic thermoplastic elastomer composites were prepared under melt mixing and passed through an open roll to orient the particles. The tensile modulus of the composites with a compatibilizer increased with increasing the particle content. The damping properties of the composites improved, compared to the neat elastomer. On the other hand, the fibrous cellulose was suspended in water, followed by wet disk-milled to prepare cellulose nanofibers(CNFs). The wet ground products showed nanoscopic fine morphology. CNFs-reinforced natural rubber(NR) composites were prepared by mixing the water suspension of CNFs with NR latex using a homogenizer. Then, it was dried in an oven and mixed again with vulcanizing ingredients of rubber using an open roll. The tensile properties of the composites improved remarkably by the addition of small amount of CNFs.

  14. Observations by electron microscopy of tracks of heavy particles in cellulose triacetate

    Energy Technology Data Exchange (ETDEWEB)

    Vareille, J.C. (Universite de Limoges, France); Decossas, J.L.; Moliton, J.P.; Teyssier, J.L.; Delaunay, B.

    1982-07-01

    Tracks of heavy charged particles have been observed in cellulose acetate by conventional electron microscopy (100 kV) and by high voltage microscopy (1, 2 MV). The tracks are formed of successive islets following each other at distances of 70 to 150 A. With the evolution of the diameter of these zones is shown the existence of a highly perturbed cylindrical volume (diameter 400 A for the case of krypton) corresponding to regions in which free radicals have been created. The different techniques used do not allow observation of the latent track because of the complications of energetic phenomena: the electron beam current density being limited, the contrast is small and hence the resolution is restricted.

  15. Evaluation the Effect of Cellulose Nanocrystalline Particles on Flexural Strength and Surface Hardness of Autoploymerized Temporary Fixed Restoration Resin

    Directory of Open Access Journals (Sweden)

    Forouzesh Shirgaee Talari

    2016-12-01

    Full Text Available Background: Autopolymerized acrylic resin is commonly used material for construction of temporary restoration; however it has insufficient mechanical properties. The purpose of this study was to evaluate the effect of adding cellulose nano-particles on flexural strength and surface hardness of auto-polymerised acrylic resin. Materials and Method: Following the acid hydrolysis of microcrystalline cellulose particles to achieve cellulose nanocrystals (CNC particles, 40 specimens were fabricated for each test that divided to four groups (n=10 coded AD. group A was the control group (without adding CNC. specimens in other three groups (B-D were reinforced with CNC at loading of 1,2.5,5 wt%. flexural strength was assessed with a three-point bending test using a universal testing machine. surface hardness testing was conducted using a Vickers hardness tester. One way ANOVA and Tucky test were used to analyzed the data.scanning electron microscopy (SEM observed was applied to evaluate the fracture pattern. Results: A significant increase in flexural strength was observed in group with 2.5% cellulose nanofillers (P=2.5%,however no significant increase was observed in surface hardness. The SEM observation demonstrated brittle fracture in pure PMMA. By adding 2.5% wt of cellulose nanofillers, the characteristics of fracture is almost ductile, but in 5% wt of nanofillers,several cracks and void was observed at fracture surface. Conclusion:Reinforcement of the Autopolymerized acrylic resin with 2.5% wt cellulose nanofillers significantly increased its flexural strength with no adverse effect on the surface hardness.

  16. Depth filters containing diatomite achieve more efficient particle retention than filters solely containing cellulose fibers

    Directory of Open Access Journals (Sweden)

    Johannes Felix Buyel

    2015-12-01

    Full Text Available The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g. when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m-2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU when diatomite filters were used. We also tested pre coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m-2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

  17. Whey protein aerogel as blended with cellulose crystalline particles or loaded with fish oil.

    Science.gov (United States)

    Ahmadi, Maede; Madadlou, Ashkan; Saboury, Ali Akbar

    2016-04-01

    Whey protein hydrogels blended with nanocrystalline and microcrystalline cellulose particles (NCC and MCC, respectively) were prepared, followed by freeze-drying, to produce aerogels. NCC blending increased the Young's modulus, and elastic character, of the protein aerogel. Aerogels were microporous and mesoporous materials, as characterized by the pores sizing 1.2 nm and 12.2 nm, respectively. Blending with NCC decreased the count of both microporous and mesoporous-classified pores at the sub-100 nm pore size range investigated. In contrast, MCC blending augmented the specific surface area and pores volume of the aerogel. It also increased moisture sorption affinity of aerogel. The feasibility of conveying hydrophobic nutraceuticals by aerogels was evaluated through loading fish oil into the non-blended aerogel. Oil loading altered its microstructure, corresponding to a peak displacement in Fourier-transform infra-red spectra, which was ascribed to increased hydrophobic interactions. Surface coating of aerogel with zein decreased the oxidation susceptibility of the loaded oil during subsequent storage.

  18. Effect of Silane Treatment on Hybridized Use of Short Cellulose Fibers and Silica Particles for Natural Rubber Reinforcement

    Science.gov (United States)

    Lopattananon, Natinee; Jitkalong, Dolmalik; Seadan, Manus; Sakai, Tadamoto

    Processability, swelling and tensile properties of natural-rubber-based hybrid composites prepared by mixing short cellulose fibers and fine silica particles of equal contents with total loading of 20 phr using a two-roll mill were analyzed. Their properties were compared with those of natural rubber reinforced with single filler (silica or cellulose fiber) and corresponding unfilled natural rubber. The tensile test showed the reinforcing effect of both single filler system and hybrid filler system in relation to natural rubber. The tensile modulus and tensile strength of hybrid composites generally laid between those of fiber-reinforced and silica-reinforced natural rubber composites, whereas the elongation at break of hybrid composites was equal to that of single filler reinforcement system. The Mooney viscosity of silica-filled compound was much higher than that of unfilled natural rubber and short fiber-filled compounds, and was significantly reduced when hybridized fillers were used. Furthermore, a silane coupling agent, Si 69, was used to modify the surface properties of cellulose fibers and silica particles. Three microscopic evaluation techniques, that is, elemental X-ray mapping (EDX), 3D microfocus X-ray scanning, and N-ARC methods were applied to investigate the filler dispersion/mixing effects. It was found that both of the fillers were more homogeneously dispersed in the hybrid composites, and the affinity between the fillers and natural rubber was improved after the silane treatment. The results from this work suggested that the better dispersion of short cellulose fiber/silica hybrid fillers had great advantages in rubber processing, and allowed for equal or higher composite strength compared to a simply silica-filled composite system.

  19. Ternary PVA nanocomposites containing cellulose nanocrystals from different sources and silver particles: part II.

    Science.gov (United States)

    Fortunati, E; Luzi, F; Puglia, D; Terenzi, A; Vercellino, M; Visai, L; Santulli, C; Torre, L; Kenny, J M

    2013-09-12

    Cellulose nanocrystals (CNC) extracted from three different sources, namely flax, phormium, and commercial microcrystalline cellulose (MCC) have been used in a polyvinyl alcohol (PVA) matrix to produce anti-bacterial films using two different amounts of silver nanoparticles (0.1 wt% and 0.5 wt%). In general, CNC confer an effect of reinforcement to PVA film, the best values of stiffness being offered by composites produced using phormium fibres, whilst for strength those produced using flax are slightly superior. This was obtained without inducing any particular modification in transition temperatures and in the thermal degradation patterns. As regards antibacterial properties, systems with CNC from flax proved slightly better than those with CNC from phormium and substantially better than those including commercial MCC. Dynamic mechanical thermal analysis (DMTA) has only been performed on the ternary composite containing 0.1 wt% Ag, which yielded higher values of Young's modulus, and as a whole confirmed the above results.

  20. Porous Cellulose Microgel Particle: A Fascinating Host for the Encapsulation, Protection, and Delivery of Lactobacillus plantarum.

    Science.gov (United States)

    Li, Wei; Luo, Xiaogang; Song, Rong; Zhu, Ya; Li, Bin; Liu, Shilin

    2016-05-04

    Advances in probiotic markets are always restrained by a low viable loading capacity and poor viability. Herein, cellulose microgels (CMs) with high porosity of 95.83 ± 0.38%, prepared by the sol-gel transition method, turned out to be a hospitable host that accommodated a large number of viable Lactobacillus plantarum higher than 10(9) colony-forming units (cfu)/g. The unique porous structure fascinated probiotics to penetrate into the core of microgels. The conjugation with alginate helped for better acid resistance and bacterial survival of the probiotics. In comparison to Ca-alginate gels, core-shell gels showed sustainable release of L. plantarum cells without damage of viability, lasting for 360 min in simulated intestine fluid. The cellulose host helped to sustain the viable cell release for a longer duration and afford better shelter for L. plantarum cells as a result of the porous structure and rigid supporting property. The core-shell gels are promising for constructing targeted delivery vehicles of bioactive nutrients.

  1. 超疏水磁性纤维素粒子的制备及性能表征%Fabrication and properties of superhydrophobic magnetic cellulose-based particles

    Institute of Scientific and Technical Information of China (English)

    黄六莲; 林新兴; 周兴满; 吴慧; 曹石林; 陈礼辉

    2016-01-01

    采用纤维素为原料,制备了超疏水磁性纤维素粒子.竹溶解浆用氢氧化钠/尿素/水体系溶解,在水中再生形成纤维素粒子.再采用原位沉淀法制得磁性纤维素粒子,正十八烷基三甲基硅烷修饰后得到超疏水磁性纤维素粒子.用扫描电镜(SEM)、傅里叶红外光谱仪(FT-IR)、热失重分析仪(TG)和液滴形状分析仪(CA)对改性纤维素粒子的形貌、化学结构、热稳定性和超疏水性进行了分析.改性纤维素粒子表现出超疏水性能和磁响应性能,水接触角达到151.2°.改性纤维素粒子可以包裹水滴和甘油形成液体弹珠.%This paper presents the preparation of superhydrophobic magnetic cellulose-based particles by using the cellulose as the raw material.The bamboo pulp is dissolved by the NaOH/urea aqueous solution,and the cellulose particles are regenerated in the water.The superhydrophobic magnetic cellulose particles are obtained by modifying the magnetic cellulose particles with the noctadecyltrimethoxysilane (ODTMS).The morphology,the chemical structure and the thermal stability of the modified cellulose particles are analyzed by the scanning electron microscopy (SEM),the Fourier transform infrared spectroscopy (FT-IR) and the thermogravimetry (TG),respectively.The modified-cellulose particles are superhydrophobic and magnetically responsive.Its water contact angle is 151.2°.The modified-cellulose particles can encapsulate the water and the glycerol droplets to form stable liquid marbles.

  2. Cellulose nanomaterials review: structure, properties and nanocomposites.

    Science.gov (United States)

    Moon, Robert J; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeff

    2011-07-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

  3. Effect of cellulose nanocrystals (CNC) particle morphology on dispersion and rheological and mechanical properties of polypropylene/CNC nanocomposites.

    Science.gov (United States)

    Khoshkava, Vahid; Kamal, Musa R

    2014-06-11

    Polypropylene (PP) nanocomposites containing spray-dried cellulose nanocrystals (CNC), freeze-dried CNC, and spray-freeze-dried CNC (CNCSFD) were prepared via melt mixing in an internal batch mixer. Polarized light, scanning electron, and atomic force microscopy showed significantly better dispersion of CNCSFD in PP/CNC nanocomposites compared with the spray-dried and freeze-dried CNCs. Rheological measurements, including linear and nonlinear viscoelastic tests, were performed on PP/CNC samples. The microscopy results were supported by small-amplitude oscillatory shear tests, which showed substantial rises in the magnitudes of key rheological parameters of PP samples containing CNCSFD. Steady-shear results revealed a strong shear thinning behavior of PP samples containing CNCSFD. Moreover, PP melts containing CNCSFD exhibited a yield stress. The magnitude of the yield stress and the degree of shear thinning behavior increased with CNCSFD concentration. It was found that CNCSFD agglomerates with a weblike structure were more effective in modifying the rheological properties. This effect was attributed to better dispersion of the agglomerates with the weblike structure. Dynamic mechanical analysis showed considerable improvement in the modulus of samples containing CNCSFD agglomerates. The percolation mechanical model with modified volume percolation threshold and filler network strength values and the Halpin-Kardos model were used to fit the experimental results.

  4. Cellulose is not just cellulose

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Felby, Claus; Johansen, Katja Salomon

    2012-01-01

    or enzymatic hydrolysis of plant cell walls is carried out simultaneously with the application of shear stress, plant cells such as fibers or tracheids break at their dislocations. At present it is not known whether specific carbohydrate binding modules (CBMs) and/or cellulases preferentially access cellulose......Most secondary plant cell walls contain irregular regions known as dislocations or slip planes. Under industrial biorefining conditions dislocations have recently been shown to play a key role during the initial phase of the enzymatic hydrolysis of cellulose in plant cell walls. In this review we...... are not regions where free cellulose ends are more abundant than in the bulk cell wall. In more severe cases cracks between fibrils form at dislocations and it is possible that the increased accessibility that these cracks give is the reason why hydrolysis of cellulose starts at these locations. If acid...

  5. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose.

    Science.gov (United States)

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-01-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future "internet of things" viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm(2), a current rectification ratio up to 4 × 10(3) between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  6. Flexible Lamination-Fabricated Ultra-High Frequency Diodes Based on Self-Supporting Semiconducting Composite Film of Silicon Micro-Particles and Nano-Fibrillated Cellulose

    Science.gov (United States)

    Sani, Negar; Wang, Xin; Granberg, Hjalmar; Andersson Ersman, Peter; Crispin, Xavier; Dyreklev, Peter; Engquist, Isak; Gustafsson, Göran; Berggren, Magnus

    2016-06-01

    Low cost and flexible devices such as wearable electronics, e-labels and distributed sensors will make the future “internet of things” viable. To power and communicate with such systems, high frequency rectifiers are crucial components. We present a simple method to manufacture flexible diodes, operating at GHz frequencies, based on self-adhesive composite films of silicon micro-particles (Si-μPs) and glycerol dispersed in nanofibrillated cellulose (NFC). NFC, Si-μPs and glycerol are mixed in a water suspension, forming a self-supporting nanocellulose-silicon composite film after drying. This film is cut and laminated between a flexible pre-patterned Al bottom electrode and a conductive Ni-coated carbon tape top contact. A Schottky junction is established between the Al electrode and the Si-μPs. The resulting flexible diodes show current levels on the order of mA for an area of 2 mm2, a current rectification ratio up to 4 × 103 between 1 and 2 V bias and a cut-off frequency of 1.8 GHz. Energy harvesting experiments have been demonstrated using resistors as the load at 900 MHz and 1.8 GHz. The diode stack can be delaminated away from the Al electrode and then later on be transferred and reconfigured to another substrate. This provides us with reconfigurable GHz-operating diode circuits.

  7. Cellulose nanomaterials review: structure, properties and nanocomposites

    OpenAIRE

    Moon, Robert J.; Martini, Ashlie; Nairn, John; Simonsen, John; Youngblood, Jeffrey

    2011-01-01

    This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction...

  8. Oxidizing Cellulose to 2,3-Dialdehyde Cellulose by Sodium Periodate

    Institute of Scientific and Technical Information of China (English)

    MENG Shuxian; FENG Yaqing; LIANG Zupei; FU Qiang; ZHANG Enzhong

    2005-01-01

    Study on oxidizing cellulose to 2,3-dialdehyde cellulose by sodium periodate (NaIO4) was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time, the particle size of 2,3-dialdehyde cellulose and alkali treatment temperature on the dialdehyde concentration of cellulose were investigated in detail. The results show that the aldehyde group content was created while reaction temperature and alkali treatment temperature increased.The most principal factors affecting the aldehyde group content of 2,3-dialdehyde cellulose were found out and the best oxidation conditions were as follows: the pH was 2, the reaction temperature was 45 ℃, the mass ratio of cellulose to NaIO4 was 1/2, the reaction time was 4 h, the alkali treatment temperature was 70 ℃ and smaller particle size was 0.80 mm.

  9. Regulating Drug Release Behavior and Kinetics from Matrix Tablets Based on Fine Particle-Sized Ethyl Cellulose Ether Derivatives: An In Vitro and In Vivo Evaluation

    Directory of Open Access Journals (Sweden)

    Kifayat Ullah Shah

    2012-01-01

    Full Text Available The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4 using PharmaTest dissolution apparatus at constant temperature of 37∘C±0.1. Similarity factor 2 was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including max, max and AUC0- were compared which showed an optimized max and max (<0.05. A good correlation was obtained between in vitro

  10. Regulating drug release behavior and kinetics from matrix tablets based on fine particle-sized ethyl cellulose ether derivatives: an in vitro and in vivo evaluation.

    Science.gov (United States)

    Shah, Kifayat Ullah; Khan, Gul Majid

    2012-01-01

    The design and fabrication of sustained/controlled release dosage forms, employing new excipients capable of extending/controlling the release of drugs from the dosage forms over prolonged periods, has worked well in achieving optimally enhanced therapeutic levels of the drugs. In this sense, the objective of this study was to investigate the suitability of selected cellulose ether derivatives for use in direct compression (DC) and as efficient drug release controlling agents. Controlled release matrix tablets of ciprofloxacin were prepared at different drug-to-polymer (D : P) ratios by direct compression using a fine particle sized ethylcellulose ether derivative (ETHOCEL Standard Premium 7FP) as rate controlling polymer. The tablets obtained were evaluated for various physico-chemical characteristics and in-vitro drug release studies were conducted in phosphate buffer (pH 7.4) using PharmaTest dissolution apparatus at constant temperature of 37 °C ± 0.1. Similarity factor f(2) was employed to the release profiles of test formulations and were compared with marketed ciprofloxacin conventional tablets. Drug release mechanism and the kinetics involved were investigated by fitting the release profile data to various kinetic models. It was found that with increasing the proportion of ethylcellulose ether derivative in the matrix, the drug release was significantly extended up to 24 hours. The tablets exhibited zero order or nearly zero order drug transport mechanism. In vivo drug release performance of the developed controlled release tablets and reference conventional tablets containing ciprofloxacin were determined in rabbit serum according to randomized two-way crossover study design using High Performance Liquid Chromatography. Several bioavailability parameters of both the test tablets and conventional tablets including C(max⁡), T(max⁡) and AUC(0-t) were compared which showed an optimized C(max⁡) and T(max⁡) (P < 0.05). A good correlation was obtained

  11. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  12. Characterization of Cellulose Microfibers Isolated from Rubberwood (Hevea brasiliensis

    Directory of Open Access Journals (Sweden)

    Junidah Lamaming

    2016-03-01

    Full Text Available Cellulose microfibers were isolated by chemical treatment followed by acid hydrolysis using sulphuric acid. The chemical compositions for extractive, holocellulose, cellulose and lignin were determined. The functional group of raw particles and cellulose microfibers of rubberwood were determined using fourier transform infrared spectroscopy (FT-IR. Morphological studies were viewed using Scanning Electron Microscopy (SEM to investigate physical changes of the fibers after acid hydrolysis. The results show that cellulose content was increased to 63 % from 52 % after hydrolysis was conducted to the raw particles. Particle size distribution of cellulose microfibers falls in the range of below 100 µm. The removal of lignin and other extractives during chemical and acid hydrolysis can be seen by the absence of certain band in the FTIR spectra. The individualization of the fibers can be seen after hydrolysis with sulphuric acid. The removal of the surface impurities along with defibrillation were also shown in the cellulose microfibers. Cellulose microfibers were isolated by chemical treatment followed by acid hydrolysis using sulphuric acid. The chemical compositions for extractive, holocellulose, cellulose and lignin were determined. The functional group of raw particles and cellulose microfibers of rubberwood were determined using fourier transform infrared spectroscopy (FT-IR. Morphological studies were viewed using Scanning Electron Microscopy (SEM to investigate physical changes of the fibers after acid hydrolysis. The results show that cellulose content was increased to 63 % from 52 % after hydrolysis was conducted to the raw particles. Particle size distribution of cellulose microfibers falls in the range of below 100 µm. The removal of lignin and other extractives during chemical and acid hydrolysis can be seen by the absence of certain band in the FTIR spectra. The individualization of the fibers can be seen after hydrolysis with

  13. Cellulose metabolism in plants.

    Science.gov (United States)

    Hayashi, Takahisa; Yoshida, Kouki; Park, Yong Woo; Konishi, Teruko; Baba, Kei'ichi

    2005-01-01

    Many bacterial genomes contain a cellulose synthase operon together with a cellulase gene, indicating that cellulase is required for cellulose biosynthesis. In higher plants, there is evidence that cell growth is enhanced by the overexpression of cellulase and prevented by its suppression. Cellulase overexpression could modify cell walls not only by trimming off the paracrystalline sites of cellulose microfibrils, but also by releasing xyloglucan tethers between the microfibrils. Mutants for membrane-anchored cellulase (Korrigan) also show a typical phenotype of prevention of cellulose biosynthesis in tissues. All plant cellulases belong to family 9, which endohydrolyzes cellulose, but are not strong enough to cause the bulk degradation of cellulose microfibrils in a plant body. It is hypothesized that cellulase participates primarily in repairing or arranging cellulose microfibrils during cellulose biosynthesis in plants. A scheme for the roles of plant cellulose and cellulases is proposed.

  14. Laser cleaning of particulates from paper: Comparison between sized ground wood cellulose and pure cellulose

    Science.gov (United States)

    Arif, S.; Kautek, W.

    2013-07-01

    Visible laser cleaning of charcoal particulates from yellow acid mechanical ground wood cellulose paper was compared with that from bleached sulphite softwood cellulose paper. About one order of magnitude of fluence range is available for a cleaning dynamics between the cleaning threshold and the destruction threshold for two laser pulses. Wood cellulose paper exhibited a higher destruction threshold of the original paper than that of the contaminated specimen because of heat transfer from the hot or evaporating charcoal particulates. In contrast, the contaminated bleached cellulose paper exhibited a higher destruction threshold due to shading by the particulates. The graphite particles are not only detached thermo-mechanically, but also by evaporation or combustion. A cleaning effect was found also outside the illuminated areas due to lateral blasting. Infrared measurements revealed dehydration/dehydrogenation reactions and cross-links by ether bonds together with structural changes of the cellulose chain arrangement and the degree of crystallinity.

  15. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  16. Cellulose gel dispersion: From pure hydrogel suspensions to encapsulated oil-in-water emulsions.

    Science.gov (United States)

    Napso, Sofia; Rein, Dmitry M; Khalfin, Rafail; Kleinerman, Olga; Cohen, Yachin

    2016-01-01

    Cellulose hydrogel particles were fabricated from molecularly-dissolved cellulose/IL solutions. The characteristics of the formed hydrogels (cellulose content, particles' size and porosity) were determined as a function of cellulose concentration in the precursor solutions. There is a significant change in the hydrogel structure when the initial cellulose solution concentration increases above about 7-9%wt. These changes include increase of the cellulose content in the hydrogel, and decrease in its pore size. The finest cellulose particle dispersions can be obtained using low concentration cellulose/IL solutions (cellulose concentration in dispersion less than 2%wt.) or hydrogels (concentration less than 1%wt.) in a dispersing medium consisting of IL with no more than 20%wt. water. Stable paraffin oil-in-water emulsions are achieved by mixing oil and water with cellulose/IL solutions. The optimal conditions for obtaining the finest particles (about 20μm in diameter) are attained using cellulose solutions of concentration between 0.7 and 4%wt. at temperature of 70°C and oil/cellulose mass ratios between 1 and 1.5.

  17. Bacterial cellulose-kaolin nanocomposites for application as biomedical wound healing materials

    Science.gov (United States)

    Wanna, Dwi; Alam, Catharina; Toivola, Diana M.; Alam, Parvez

    2013-12-01

    This short communication provides preliminary experimental details on the structure-property relationships of novel biomedical kaolin-bacterial cellulose nanocomposites. Bacterial cellulose is an effective binding agent for kaolin particles forming reticulated structures at kaolin-cellulose interfaces and entanglements when the cellulose fraction is sufficiently high. The mechanical performance of these materials hence improves with an increased fraction of bacterial cellulose, though this also causes the rate of blood clotting to decrease. These composites have combined potential as both short-term (kaolin) and long-term (bacterial cellulose) wound healing materials.

  18. Parameter and Process Significance in Mechanistic Modeling of Cellulose Hydrolysis

    Science.gov (United States)

    Rotter, B.; Barry, A.; Gerhard, J.; Small, J.; Tahar, B.

    2005-12-01

    The rate of cellulose hydrolysis, and of associated microbial processes, is important in determining the stability of landfills and their potential impact on the environment, as well as associated time scales. To permit further exploration in this field, a process-based model of cellulose hydrolysis was developed. The model, which is relevant to both landfill and anaerobic digesters, includes a novel approach to biomass transfer between a cellulose-bound biofilm and biomass in the surrounding liquid. Model results highlight the significance of the bacterial colonization of cellulose particles by attachment through contact in solution. Simulations revealed that enhanced colonization, and therefore cellulose degradation, was associated with reduced cellulose particle size, higher biomass populations in solution, and increased cellulose-binding ability of the biomass. A sensitivity analysis of the system parameters revealed different sensitivities to model parameters for a typical landfill scenario versus that for an anaerobic digester. The results indicate that relative surface area of cellulose and proximity of hydrolyzing bacteria are key factors determining the cellulose degradation rate.

  19. Investigation of the physico-mechanical properties of electrospun PVDF/cellulose nanofibers.

    OpenAIRE

    Issa, A. A. [احمد عبد السلام عيسى; Al-Maadeed, M.; Luyt,A.S.; Mrlik, M.; Hassan, M. K.

    2016-01-01

    The electro-activity and mechanical properties of PVDF depends mainly on the b-phase content and degree of crystallinity. In this study, cellulose fibers were used to improve these characteristics. This could be achieved because the hydroxyl groups on cellulose would force the fluorine atoms in PVDF to be in the trans-conformation, and the cellulose particles could act as nucleation centers. Electrospinning was used to prepare the PVDF/cellulose (nano)fibrous films, and this improved the tota...

  20. Preparation of silver nano-particles immobilized onto chitin nano-crystals and their application to cellulose paper for imparting antimicrobial activity.

    Science.gov (United States)

    Li, Zhihan; Zhang, Ming; Cheng, Dong; Yang, Rendang

    2016-10-20

    Immobilized silver nano-particles (Ag NPs) possess excellent antimicrobial properties due to their unique surface characteristics. In this paper, immobilized silver nano-particles were synthesized in the presence of chitin nano-crystals (CNC) based on the Tollens mechanism (reduction of silver ion by aldehydes in the chitosan oligosaccharides (COS)) under microwave-assisted conditions. The prepared Ag NPs-loaded CNC nano-composites were then applied onto the paper surface via coating for the preparation of antibacterial paper. Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) results confirmed that the Ag NPs were immobilized onto the CNC. The transmission electron microscope (TEM) and scanning electron microscopy (SEM) results further revealed that the spherical Ag NPs (5-12nm) were well dispersed on the surface of CNC. The coated paper made from the Ag NPs-loaded CNC nano-composites exhibited a high effectiveness of the antibacterial activity against E. coli or S. aureus.

  1. Cellulose binding domain proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc; Doi, Roy

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  2. Cellulose Degradation by Cellulose-Clearing and Non-Cellulose-Clearing Brown-Rot Fungi

    OpenAIRE

    Highley, Terry L.

    1980-01-01

    Cellulose degradation by four cellulose-clearing brown-rot fungi in the Coniophoraceae—Coniophora prasinoides, C. puteana, Leucogyrophana arizonica, and L. olivascens—is compared with that of a non-cellulose-clearing brown-rot fungus, Poria placenta. The cellulose- and the non-cellulose-clearing brown-rot fungi apparently employ similar mechanisms to depolymerize cellulose; most likely a nonenzymatic mechanism is involved.

  3. Surface modification of cellulose nanocrystals

    Institute of Scientific and Technical Information of China (English)

    WANG Neng; DING Enyong; CHENG Rongshi

    2007-01-01

    In order to improve the dispersibility of cellulose nanocrystal(CNC) particles,three difierent grafted reactions of acetylation,hydroxyethylation and hydroxypropylation were introduced to modify the CNC surface.The main advantages of these methods were the simple and easily controlled reaction conditions,and the dispersibility of the resulting products was distinctly improved.The properties of the modified CNC were characterized by means of Fourier transform infrared spectroscopy(FT-IR),13 C nuclear magnetic resonance(NMR),transmission electron microscopy(TEM)and thermogravimetric analyses(TGA).The results indicated mat after desiccation,the modification products could be dispersed again in the proper solvents by ultrasonic treatments,and the diameter of their particles had no obvious changes.However,their thermal degradation behaviors were quite different.The initial decomposition temperature of the modified products via hydroxyethylation or hydroxypropylation was lower than that of modified products via acetylation.

  4. Hazy Transparent Cellulose Nanopaper

    Science.gov (United States)

    Hsieh, Ming-Chun; Koga, Hirotaka; Suganuma, Katsuaki; Nogi, Masaya

    2017-01-01

    The aim of this study is to clarify light scattering mechanism of hazy transparent cellulose nanopaper. Clear optical transparent nanopaper consists of 3–15 nm wide cellulose nanofibers, which are obtained by the full nanofibrillation of pulp fibers. At the clear transparent nanopaper with 40 μm thickness, their total transmittance are 89.3–91.5% and haze values are 4.9–11.7%. When the pulp fibers are subjected to weak nanofibrillation, hazy transparent nanopapers are obtained. The hazy transparent nanopaper consists of cellulose nanofibers and some microsized cellulose fibers. At the hazy transparent nanopaper with 40 μm thickness, their total transmittance were constant at 88.6–92.1% but their haze value were 27.3–86.7%. Cellulose nanofibers are solid cylinders, whereas the pulp fibers are hollow cylinders. The hollow shape is retained in the microsized cellulose fibers, but they are compressed flat inside the nanopaper. This compressed cavity causes light scattering by the refractive index difference between air and cellulose. As a result, the nanopaper shows a hazy transparent appearance and exhibits a high thermal durability (295–305 °C), and low thermal expansion (8.5–10.6 ppm/K) because of their high density (1.29–1.55 g/cm3) and crystallinity (73–80%).

  5. Precipitated calcium carbonate (PCC - cellulose composite fillers: Effects of PCC particle structure on the production and properties of uncoated fine paper

    Directory of Open Access Journals (Sweden)

    Paulapuro, H.

    2007-02-01

    Full Text Available This work examines the precipitation of PCC – pulp composite fillers with varying crystal habits and their effects on the papermaking properties of printing and writing paper. Colloidal (c-PCC, rhombohedral (r-PCC, and scalenohedral types (s-PCC of composite PCCs were produced and compared with commercial reference PCCs. Scanning electron micros-copy showed the c-PCC to be a high-surface-area nano-structured PCC. The rhombohedral composite was formed in clusters like a spider-web structure. Under similar experimental conditions, composite PCC was formed as individual ellipsoidal crystals and some of the particles had malformed structure, in contrast to the structured reference s-PCC. The co-precipitation and the structure of PCC significantly influence the forming, consolidation, and properties of paper, as well as its perform-ance in printing.Composite c-PCC showed the highest retention during forming. At higher filler contents, dewatering was reduced significantly with handsheets containing s- and r-PCC composite fillers. Colloidal composite hand-sheets showed the lowest tensile index and internal bond strength, while the rhombohedral composite gave the highest z-directional bond strength. Compared with the traditional reference samples containing commercial PCCs, paper with s- and r-composites had significantly higher density but similar light scattering ability. Addition of fibrillar fines to fine paper increased print rub fastness significantly in both laser and inkjet printed samples.

  6. Overview of Cellulose Nanomaterials, Their Capabilities and Applications

    Science.gov (United States)

    Moon, Robert J.; Schueneman, Gregory T.; Simonsen, John

    2016-09-01

    Cellulose nanomaterials (CNs) are a new class of cellulose particles with properties and functionalities distinct from molecular cellulose and wood pulp, and as a result, they are being developed for applications that were once thought impossible for cellulosic materials. Momentum is growing in CN research and development, and commercialization in this field is happening because of the unique combination of characteristics (e.g., high mechanical properties, sustainability, and large-scale production potential) and utility across a broad spectrum of material applications (e.g. as an additive, self-sustaining structures, and template structures) that CNs offer. Despite the challenges typical for materials development, CN and near-CN production is ramping up with pilot scale to industry demonstration trials, and the first commercial products are starting to hit the marketplace. This review provides a broad overview of CNs and their capabilities that are enabling new application areas for cellulose-based materials.

  7. Fulton Cellulosic Ethanol Biorefinery

    Energy Technology Data Exchange (ETDEWEB)

    Sumait, Necy [BlueFire Ethanol, Irvine, CA (United States); Cuzens, John [BlueFire Ethanol, Irvine, CA (United States); Klann, Richard [BlueFire Ethanol, Irvine, CA (United States)

    2015-07-24

    Final report on work performed by BlueFire on the deployment of acid hydrolysis technology to convert cellulosic waste materials into renewable fuels, power and chemicals in a production facility to be located in Fulton, Mississippi.

  8. Water-repellent cellulose fiber networks with multifunctional properties.

    Science.gov (United States)

    Bayer, Ilker S; Fragouli, Despina; Attanasio, Agnese; Sorce, Barbara; Bertoni, Giovanni; Brescia, Rosaria; Di Corato, Riccardo; Pellegrino, Teresa; Kalyva, Maria; Sabella, Stefania; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2011-10-01

    We demonstrate a simple but highly efficient technique to introduce multifunctional properties to cellulose fiber networks by wetting them with ethyl-cyanoacrylate monomer solutions containing various suspended organic submicrometer particles or inorganic nanoparticles. Solutions can be applied on cellulosic surfaces by simple solution casting techniques or by dip coating, both being suitable for large area applications. Immediately after solvent evaporation, ethyl-cyanoacrylate starts cross-linking around cellulose fibers under ambient conditions because of naturally occurring surface hydroxyl groups and adsorbed moisture, encapsulating them with a hydrophobic polymer shell. Furthermore, by dispersing various functional particles in the monomer solutions, hydrophobic ethyl-cyanoacrylate nanocomposites with desired functionalities can be formed around the cellulose fibers. To exhibit the versatility of the method, cellulose sheets were functionalized with different ethyl-cyanoacrylate nanocomposite shells comprising submicrometer wax or polytetrafluoroethylene particles for superhydophobicity, MnFe(2)O(4) nanoparticles for magnetic activity, CdSe/ZnS quantum dots for light emission, and silver nanoparticles for antimicrobial activity. Morphological and functional properties of each system have been studied by scanning and transmission electron microscopy, detailed contact angle measurements, light emission spectra and E. coli bacterial growth measurements. A plethora of potential applications can be envisioned for this technique, such as food and industrial packaging, document protection, catalytic cellulosic membranes, textronic (electrofunctional textiles), electromagnetic devices, authentication of valuable documents, and antimicrobial wound healing products to name a few.

  9. The cellulose resource matrix.

    Science.gov (United States)

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G

    2013-03-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  10. Acid hydrolysis of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Salazar, H.

    1980-12-01

    One of the alternatives to increase world production of etha nol is by the hydrolysis of cellulose content of agricultural residues. Studies have been made on the types of hydrolysis: enzimatic and acid. Data obtained from the sulphuric acid hydrolysis of cellulose showed that this process proceed in two steps, with a yield of approximately 95% glucose. Because of increases in cost of alternatives resources, the high demand of the product and the more economic production of ethanol from cellulose materials, it is certain that this technology will be implemented in the future. At the same time further studies on the disposal and reuse of the by-products of this production must be undertaken.

  11. Cellulose Microfibril Formation by Surface-Tethered Cellulose Synthase Enzymes.

    Science.gov (United States)

    Basu, Snehasish; Omadjela, Okako; Gaddes, David; Tadigadapa, Srinivas; Zimmer, Jochen; Catchmark, Jeffrey M

    2016-02-23

    Cellulose microfibrils are pseudocrystalline arrays of cellulose chains that are synthesized by cellulose synthases. The enzymes are organized into large membrane-embedded complexes in which each enzyme likely synthesizes and secretes a β-(1→4) glucan. The relationship between the organization of the enzymes in these complexes and cellulose crystallization has not been explored. To better understand this relationship, we used atomic force microscopy to visualize cellulose microfibril formation from nickel-film-immobilized bacterial cellulose synthase enzymes (BcsA-Bs), which in standard solution only form amorphous cellulose from monomeric BcsA-B complexes. Fourier transform infrared spectroscopy and X-ray diffraction techniques show that surface-tethered BcsA-Bs synthesize highly crystalline cellulose II in the presence of UDP-Glc, the allosteric activator cyclic-di-GMP, as well as magnesium. The cellulose II cross section/diameter and the crystal size and crystallinity depend on the surface density of tethered enzymes as well as the overall concentration of substrates. Our results provide the correlation between cellulose microfibril formation and the spatial organization of cellulose synthases.

  12. CHARACTERIZATION OF REGENERATED CELLULOSE MEMBRANES HYDROLYZED FROM CELLULOSE ACETATE

    Institute of Scientific and Technical Information of China (English)

    Yun Chen; Xiao-peng Xiong; Guang Yang; Li-na Zhang; Sen-lin Lei; Hui Lianga

    2002-01-01

    A series of cellulose acetate membranes were prepared by using formamide as additive, and then were hydrolyzedin 4 wt% aqueous NaOH solution for 8 h to obtain regenerated cellulose membranes. The dependence of degree ofsubstitution, structure, porous properties, solubility and thermal stability on hydrolysis time was studied by chemical titration,Fourier transform infrared spectroscopy, scanning electron microscopy, wide-angle X-ray diffraction, and differentialscanning calorimetry, respectively. The results indicated that the pore size of the regenerated cellulose membranes wasslightly smaller than that of cellulose acetate membrane, while solvent-resistance, crystallinity and thermostability weresignificantly improved. This work provides a simple way to prepare the porous cellulose membranes, which not only kept thegood pore characteristics of cellulose acetate membranes, but also possessed solvent-resistance, high crystallinity andthermostability. Therefore, the application range of cellulose acetate membranes can be expanded.

  13. Influence of Crystal Allomorph and Crystallinity on the Products and Behavior of Cellulose during Fast Pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Mukarakate, Calvin; Mittal, Ashutosh; Ciesielski, Peter N.; Budhi, Sridhar; Thompson, Logan; Iisa, Kristiina; Nimlos, Mark R.; Donohoe, Bryon S.

    2016-09-06

    Cellulose is the primary biopolymer responsible for maintaining the structural and mechanical integrity of cell walls and, during the fast pyrolysis of biomass, may be restricting cell wall expansion and inhibiting phase transitions that would otherwise facilitate efficient escape of pyrolysis products. Here, we test whether modifications in two physical properties of cellulose, its crystalline allomorph and degree of crystallinity, alter its performance during fast pyrolysis. We show that both crystal allomorph and relative crystallinity of cellulose impact the slate of primary products produced by fast pyrolysis. For both cellulose-I and cellulose-II, changes in crystallinity dramatically impact the fast pyrolysis product portfolio. In both cases, only the most highly crystalline samples produced vapors dominated by levoglucosan. Cellulose-III, on the other hand, produces largely the same slate of products regardless of its relative crystallinity and produced as much or more levoglucosan at all crystallinity levels compared to cellulose-I or II. In addition to changes in products, the different cellulose allomorphs affected the viscoelastic properties of cellulose during rapid heating. Real-time hot-stage pyrolysis was used to visualize the transition of the solid material through a molten phase and particle shrinkage. SEM analysis of the chars revealed additional differences in viscoelastic properties and molten phase behavior impacted by cellulose crystallinity and allomorph. Regardless of relative crystallinity, the cellulose-III samples displayed the most obvious evidence of having transitioned through a molten phase.

  14. Bacterial Cellulose From Rice Waste Water With Addition Chitosan, Glycerol, And Silver Nanoparticle

    Directory of Open Access Journals (Sweden)

    Eli Rohaeti

    2016-05-01

    Full Text Available This study aimed to prepare silver nanoparticles chemically, deposite silver nanoparticles on bacterial cellulose-chitosan-glycerol composite based rice waste water, as well as test the antibacterial activity of bacterial cellulose and its composite. Preparation of silver nanoparticles was conducted by chemical reduction of silver nitrate solution, as well as trisodium citrate as the reductor. Bacterial cellulose from rice waste water is fermented by the bacteria Acetobacter xylinum for 7 days. The dried bacterial cellulose was composited with chitosan and glycerol by immersion method on 2% of chitosan solution and 0.5% of glycerol solution. UV-Vis spectroscopy is used to determine the formation of silvernanoparticles and Particle Size Analyzer to test the size and particle size distribution. Characterization was conducted to bacterial cellulose and its composite included functional groups by FTIR, the mechanical properties by Tensile Tester, crystallinity by XRD, surface photograph by SEM, and antibacterial test against S. aureus and E. coli by the shake flask turbidimetry method. Silver nanoparticle characterization indicated that silver nanoparticles are formed at a wavelength of 421.80 nm, yellow, diameter particle size of 61.8 nm. SEM images showed that the surface of bacterial cellulose had deposited silver nanoparticles and antibacterial test showed an inhibitory effect of bacterial cellulose, bacterial cellulose-chitosan composite, and bacterial cellulose-chitosan-glycerol composite which are deposited silver nanoparticles against the growth of S. aureus and E. coli bacteria.

  15. Size distribution and seasonal variation of atmospheric cellulose

    Science.gov (United States)

    Puxbaum, Hans; Tenze-Kunit, Monika

    Atmospheric cellulose is a main constituent of the insoluble organic aerosol and a "macrotracer" for plant debris. A time series of the cellulose concentration at a downtown site in Vienna showed a maximum concentration during fall and a secondary maximum during spring. The fall maximum appears to be associated with leaf litter production, the spring maximum with increased biological activity involving repulsion of cellulose-containing particles, e.g. seed production. The grand average of the time series over 9 months was 0.374 μg m -3 cellulose, respectively, 0.75 μg m -3 plant debris. Compared to an annual average of 5.7 μg m -3 organic carbon as observed at a Vienna downtown site it becomes clear that plant debris is a major contributor to the organic aerosol and has to be considered in source attribution studies. Simultaneous measurements at the downtown and a suburban site indicated that particulate cellulose is obviously not produced within the city in notable amounts, at least during the campaign in December. Size distribution measurements with impactors showed the unexpected result that "fine aerosol" size particles (0.1- 1.6 μm aerodynamic diameter) contained 0.7% "free cellulose" on a mass basis, forming a wettable, but insoluble part of the accumulation mode aerosol.

  16. Calculating cellulose diffraction patterns

    Science.gov (United States)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  17. The cellulose resource matrix

    NARCIS (Netherlands)

    Keijsers, E.R.P.; Yilmaz, G.; Dam, van J.E.G.

    2013-01-01

    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where

  18. Novel Composite Materials for Chiral Separation from Cellulose and Barium Sulfate

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2013-01-01

    Full Text Available Cellulose was dissolved in an aqueous solution of sodium hydroxide (NaOH and urea followed by the addition of barium sulfate (BaSO4 to yield the BaSO4/cellulose composite particles. The morphology, particle size, and BaSO4 content of the composite particles were adjusted by controlling the feed ratio of cellulose and BaSO4. The cellulose within the composite particles then reacted with 3,5-dimethylphenyl isocyanate. The resulting materials were utilized as the chiral stationary phases (CSPs whose enantioseparation capabilities were evaluated by various chiral analytes. Due to the mechanical enhancement effect of BaSO4, the composite particles could be applied to the chromatographic packing materials.

  19. Cellulose Isolation Methodology for NMR Analysis of Cellulose Ultrastructure

    Directory of Open Access Journals (Sweden)

    Art J. Ragauskas

    2011-11-01

    Full Text Available In order to obtain accurate information about the ultrastructure of cellulose from native biomass by 13C cross polarization magic angle spinning (CP/MAS NMR spectroscopy the cellulose component must be isolated due to overlapping resonances from both lignin and hemicellulose. Typically, cellulose isolation has been achieved via holocellulose pulping to remove lignin followed by an acid hydrolysis procedure to remove the hemicellulose components. Using 13C CP/MAS NMR and non-linear line-fitting of the cellulose C4 region, it was observed that the standard acid hydrolysis procedure caused an apparent increase in crystallinity of ~10% or less on the cellulose isolated from Populus holocellulose. We have examined the effect of the cellulose isolation method, particularly the acid treatment time for hemicellulose removal, on cellulose ultrastructural characteristics by studying these effects on cotton, microcrystalline cellulose (MCC and holocellulose pulped Populus. 13C CP/MAS NMR of MCC indicated that holocellulose pulping and acid hydrolysis has little effect on the crystalline ultrastructural components of cellulose. Although any chemical method to isolate cellulose from native biomass will invariably alter substrate characteristics, especially those related to regions accessible to solvents, we found those changes to be minimal and consistent in samples of typical crystallinity and lignin/hemicellulose content. Based on the rate of the hemicellulose removal, as determined by HPLC-carbohydrate analysis and magnitude of cellulose ultrastructural alteration, the most suitable cellulose isolation methodology utilizes a treatment of 2.5 M HCl at 100 °C for a standard residence time between 1.5 and 4 h. However, for the most accurate crystallinity results this residence time should be determined empirically for a particular sample.

  20. Effects of Soybean Oil Modified Cellulose Fibril and Organosilane Modified Cellulose Fibril on Crystallization of Polypropylene

    Directory of Open Access Journals (Sweden)

    Sarit Thanomchat

    2015-01-01

    Full Text Available Soybean oil modified cellulose fibril (Oil-g-CF and organosilane modified cellulose fibril (Silane-g-CF were prepared using maleinized soybean oil and hexadecyltrimethoxysilane, respectively. Thus obtained modified cellulose fibril was added to polypropylene by a simple melt mixing on a hotplate. PP/modified CF composites with 4.0 wt% filler content were prepared. The composites were subject to a polarized optical microscope to investigate particle dispersion, supramolecular morphology, and crystallization behavior. It was found that Silane-g-CF exhibited smaller particle sizes with better particle distribution when compared to Oil-g-CF. In addition, the etched composite samples unveiled an increase in a number of spherulite crystals as well as a decrease in the spherulite size. The nonisothermal crystallization study of composites revealed that both Oil-g-CF and Silane-g-CF were capable of nucleating PP by facilitating faster crystallization process and raising the number of spherulites. The DSC results indicated that Silane-g-CF was able to perform a more effective nucleation than Oil-g-CF, judged by a higher crystallization temperature. Moreover, PP composites containing Oil-g-CF and Silane-g-CF had higher crystallinity by 7% and 10%, for the first and the latter, respectively, when compared to neat PP.

  1. Cellulose biogenesis in Dictyostelium discoideum

    Energy Technology Data Exchange (ETDEWEB)

    Blanton, R.L.

    1993-12-31

    Organisms that synthesize cellulose can be found amongst the bacteria, protistans, fungi, and animals, but it is in plants that the importance of cellulose in function (as the major structural constituent of plant cell walls) and economic use (as wood and fiber) can be best appreciated. The structure of cellulose and its biosynthesis have been the subjects of intense investigation. One of the most important insights gained from these studies is that the synthesis of cellulose by living organisms involves much more than simply the polymerization of glucose into a (1{r_arrow}4)-{beta}-linked polymer. The number of glucoses in a polymer (the degree of polymerization), the crystalline form assumed by the glucan chains when they crystallize to form a microfibril, and the dimensions and orientation of the microfibrils are all subject to cellular control. Instead of cellulose biosynthesis, a more appropriate term might be cellulose biogenesis, to emphasize the involvement of cellular structures and mechanisms in controlling polymerization and directing crystallization and deposition. Dictyostelium discoideum is uniquely suitable for the study of cellulose biogenesis because of its amenability to experimental study and manipulation and the extent of our knowledge of its basic cellular mechanisms (as will be evident from the rest of this volume). In this chapter, I will summarize what is known about cellulose biogenesis in D. discoideum, emphasizing its potential to illuminate our understanding both of D. discoideum development and plant cellulose biogenesis.

  2. Effects of freeze drying and silver staining on carbonization of cellulose: carbon nano-materials

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae-Young; Im, Hyun Sik [Dongguk University, Seoul (Korea, Republic of)

    2012-05-15

    We investigated the effects of sulfuric acid and silver particles on the carbonization of natural cellulose from Halocynthia. We carried out thermogravimetry and used transmission electron microscopy measurements to study the yield of carbon and the structure of the carbonized nano-fiber. We found that the addition of sulfuric acid and silver particles to the cellulose fiber enhanced the yield of carbon while keeping the original structure of the carbon nano-fiber.

  3. Drying of Pigment-Cellulose Nanofibril Substrates

    Directory of Open Access Journals (Sweden)

    Oleg Timofeev

    2014-10-01

    Full Text Available A new substrate containing cellulose nanofibrils and inorganic pigment particles has been developed for printed electronics applications. The studied composite structure contains 80% fillers and is mechanically stable and flexible. Before drying, the solids content can be as low as 20% due to the high water binding capacity of the cellulose nanofibrils. We have studied several drying methods and their effects on the substrate properties. The aim is to achieve a tight, smooth surface keeping the drying efficiency simultaneously at a high level. The methods studied include: (1 drying on a hot metal surface; (2 air impingement drying; and (3 hot pressing. Somewhat surprisingly, drying rates measured for the pigment-cellulose nanofibril substrates were quite similar to those for the reference board sheets. Very high dewatering rates were observed for the hot pressing at high moisture contents. The drying method had significant effects on the final substrate properties, especially on short-range surface smoothness. The best smoothness was obtained with a combination of impingement and contact drying. The mechanical properties of the sheets were also affected by the drying method and associated temperature.

  4. Acetoacetylation of Hydroxyethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    陈晓锋; 高彦芳; 杜奕; 刘德山

    2002-01-01

    The acetoacetyl group can be used to improve superabsorbent resins since it is more active than the hydroxyethyl group. The acetoacetyl group can be introduced into the side group of hydroxyethyl cellulose (HEC) to activate HEC using the ester exchange reaction between HEC and ethyl acetoacetate (EAA) to improve HEC grafting. This paper discusses the main factors affecting the reaction, such as the amount of EAA and catalyzer, the reaction temperature, and the reaction time. The acetoacetyl group was successfully introduced into HEC. Within specified ranges, increasing the amount of EAA, the reaction temperature and the reaction time will increase the acetoacetylation.

  5. Cellulose binding domain fusion proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1998-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  6. Cellulose Synthesis in Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Alan R. White; Ann G. Matthysse

    2004-07-31

    We have cloned the celC gene and its homologue from E. coli, yhjM, in an expression vector and expressed the both genes in E. coli; we have determined that the YhjM protein is able to complement in vitro cellulose synthesis by extracts of A. tumefaciens celC mutants, we have purified the YhjM protein product and are currently examining its enzymatic activity; we have examined whole cell extracts of CelC and various other cellulose mutants and wild type bacteria for the presence of cellulose oligomers and cellulose; we have examined the ability of extracts of wild type and cellulose mutants including CelC to incorporate UDP-14C-glucose into cellulose and into water-soluble, ethanol-insoluble oligosaccharides; we have made mutants which synthesize greater amounts of cellulose than the wild type; and we have examined the role of cellulose in the formation of biofilms by A. tumefaciens. In addition we have examined the ability of a putative cellulose synthase gene from the tunicate Ciona savignyi to complement an A. tumefaciens celA mutant. The greatest difference between our knowledge of bacterial cellulose synthesis when we started this project and current knowledge is that in 1999 when we wrote the original grant very few bacteria were known to synthesize cellulose and genes involved in this synthesis were sequenced only from Acetobacter species, A. tumefaciens and Rhizobium leguminosarum. Currently many bacteria are known to synthesize cellulose and genes that may be involved have been sequenced from more than 10 species of bacteria. This additional information has raised the possibility of attempting to use genes from one bacterium to complement mutants in another bacterium. This will enable us to examine the question of which genes are responsible for the three dimensional structure of cellulose (since this differs among bacterial species) and also to examine the interactions between the various proteins required for cellulose synthesis. We have carried out one

  7. Ultrasonic dyeing of cellulose nanofibers.

    Science.gov (United States)

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

  8. Preparation and Characterization of Cellulose Microcrystalline (MCC) from Fiber of Empty Fruit Bunch Palm Oil

    Science.gov (United States)

    Nasution, H.; Yurnaliza; Veronicha; Irmadani; Sitompul, S.

    2017-03-01

    Alpha cellulose which was isolated from cellulose of fiber empty fruit bunch palm oil was hidrolized with hydrochloric acid (2,5N) at 80°C to produce microcrystalline cellulose (MCC). Microcrystalline cellulose is an important additional ingredient in the pharmaceutical, food, cosmetics, and structural composites. In this study, MCC, alpha cellulose, and cellulose were characterized and thereafter were compared. Characterizations were made using some equipment such as x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and thermogravimetry analyzer (TGA). X-ray diffraction and infrared spectroscopy were studied to determine crystallinity and molecular structure of MCC, where scanning electron microscopy images were conducted for information about morfology of MCC. Meanwhile, thermal resistance of MCC was determined using thermogravimetry analyzer (TGA). From XRD and FTIR, the obtained results showed that the crystalline part was traced on MCC, where the –OH and C-O groups tended to reduced as alpha cellulose has changed to MCC. From SEM the image showed the reduction of particle size of MCC, while the thermal resistance of MCC was found lower as compared with cellulose and alpha cellulose as well, which was attributed to the lower molecular weight of MCC.

  9. SYNTHESIS AND CHARACTERIZATION OF CELLULOSE-SILICA COMPOSITE FIBER IN ETHANOL/WATER MIXED SOLVENTS

    Directory of Open Access Journals (Sweden)

    Ning Jia

    2011-04-01

    Full Text Available Cellulose-silica composite fiber samples have been successfully synthesized using cellulose solution, tetraethoxysilane, and NH3•H2O in ethanol/water mixed solvents at room temperature for 24 h. The cellulose solution was previously prepared by the dissolution of microcrystalline cellulose in a solvent mixture of N,N-dimethylacetamide (DMAc/lithium chloride (LiCl. The effect of the tetraethoxysilane concentration on the product was investigated. The products were characterized by X-ray powder diffraction (XRD, thermogravimetric analysis (TG, differential scanning calorimetric analysis (DSC, scanning electron microscopy (SEM, Fourier transform infrared spectrometry (FT-IR, energy-dispersive X-ray spectrum (EDS, and cross polarization magic angle spinning (CP/MAS solid state 13C-NMR. The morphology of the cellulose-silica composite fiber was investigated by SEM, while their composition was established from EDS measurements combined with the results of FT-IR spectral analysis and XRD patterns. The XRD, FT-IR and EDS results indicated that the obtained product was cellulose-silica composite fiber. The SEM micrographs showed that the silica particles were homogeneously dispersed in the cellulose fiber. The CP/MAS solid state 13C-NMR results indicated that the silica concentration had an influence on the crystallinity of the cellulose. This method is simple for preparation of cellulose-based composites.

  10. Preparation and Determination of Drug-Polymer Interaction and In-vitro Release of Didanosine Microspheres made of Cellulose Acetate Phthalate or Ethyl cellulose Polymers

    OpenAIRE

    Sethi R. K; Barik B. B.; Sahoo S. K.

    2013-01-01

    The objective of this study was to formulate and evaluate the drug-polymer interaction of Didanosine using two polymers with different characteristics as Ethyl cellulose or Cellulose acetate phthalate. Microspheres were prepared by the emulsion solvent evaporation. The effect of drug-polymer interaction was studied for each of microspheres. Important parameters in the evaluation of a microencapsulation technique are encapsulation efficiency, yield production, particle size, surface characteri...

  11. Functional biocompatible magnetite-cellulose nanocomposite fibrous networks: Characterization by fourier transformed infrared spectroscopy, X-ray powder diffraction and field emission scanning electron microscopy analysis.

    Science.gov (United States)

    Habibi, Neda

    2015-02-05

    The preparation and characterization of functional biocompatible magnetite-cellulose nano-composite fibrous material is described. Magnetite-cellulose nano-composite was prepared by a combination of the solution-based formation of magnetic nano-particles and subsequent coating with amino celluloses. Characterization was accomplished using X-ray powder diffraction (XRD), fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. The peaks of Fe3O4 in the XRD pattern of nanocomposite confirm existence of the nanoparticles in the amino cellulose matrix. Magnetite-cellulose particles exhibit an average diameter of roughly 33nm as demonstrated by field emission scanning electron microscopy. Magnetite nanoparticles were irregular spheres dispersed in the cellulose matrix. The vibration corresponding to the NCH3 functional group about 2850cm(-1) is assigned in the FTIR spectra. Functionalized magnetite-cellulose nano-composite polymers have a potential range of application as targeted drug delivery system in biomedical field.

  12. Cellulose nanocrystals: synthesis, functional properties, and applications

    OpenAIRE

    George J.; Sabapathi SN

    2015-01-01

    Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers...

  13. 21 CFR 172.868 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethyl cellulose. 172.868 Section 172.868 Food and... Multipurpose Additives § 172.868 Ethyl cellulose. The food additive ethyl cellulose may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is a cellulose...

  14. 21 CFR 573.420 - Ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethyl cellulose. 573.420 Section 573.420 Food and... Listing § 573.420 Ethyl cellulose. The food additive ethyl cellulose may be safely used in animal feed in accordance with the following prescribed conditions: (a) The food additive is a cellulose ether...

  15. Cellulose Nanomaterials in Water Treatment Technologies

    OpenAIRE

    Carpenter, Alexis Wells; de Lannoy, Charles François; Mark R. Wiesner

    2015-01-01

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials’ potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials’ beneficial role in environmental remediation and membranes for water filtration, ...

  16. Preparation of biocompatible magnetite-carboxymethyl cellulose nanocomposite: Characterization of nanocomposite by FTIR, XRD, FESEM and TEM

    Science.gov (United States)

    Habibi, Neda

    2014-10-01

    The preparation and characterization of magnetite-carboxymethyl cellulose nano-composite (M-CMC) material is described. Magnetite nano-particles were synthesized by a modified co-precipitation method using ferrous chloride tetrahydrate and ferric chloride hexahydrate in ammonium hydroxide solution. The M-CMC nano-composite particles were synthesized by embedding the magnetite nanoparticles inside carboxymethyl cellulose (CMC) using a freshly prepared mixture of Fe3O4 with CMC precursor. Morphology, particle size, and structural properties of magnetite-carboxymethyl cellulose nano-composite was accomplished using X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared (FTIR) and field emission scanning electron microscopy (FESEM) analysis. As a result, magnetite nano-particles with an average size of 35 nm were obtained. The biocompatible Fe3O4-carboxymethyl cellulose nano-composite particles obtained from the natural CMC polymers have a potential range of application in biomedical field.

  17. Acetobixan, an inhibitor of cellulose synthesis identified by microbial bioprospecting.

    Directory of Open Access Journals (Sweden)

    Ye Xia

    Full Text Available In plants, cellulose biosynthesis is an essential process for anisotropic growth and therefore is an ideal target for inhibition. Based on the documented utility of small-molecule inhibitors to dissect complex cellular processes we identified a cellulose biosynthesis inhibitor (CBI, named acetobixan, by bio-prospecting among compounds secreted by endophytic microorganisms. Acetobixan was identified using a drug-gene interaction screen to sift through hundreds of endophytic microbial secretions for one that caused synergistic reduction in root expansion of the leaky AtcesA6prc1-1 mutant. We then mined this microbial secretion for compounds that were differentially abundant compared with Bacilli that failed to mimic CBI action to isolate a lead pharmacophore. Analogs of this lead compound were screened for CBI activity, and the most potent analog was named acetobixan. In living Arabidopsis cells visualized by confocal microscopy, acetobixan treatment caused CESA particles localized at the plasma membrane (PM to rapidly re-localize to cytoplasmic vesicles. Acetobixan inhibited 14C-Glc uptake into crystalline cellulose. Moreover, cortical microtubule dynamics were not disrupted by acetobixan, suggesting specific activity towards cellulose synthesis. Previous CBI resistant mutants such as ixr1-2, ixr2-1 or aegeus were not cross resistant to acetobixan indicating that acetobixan targets a different aspect of cellulose biosynthesis.

  18. Acetobixan, an inhibitor of cellulose synthesis identified by microbial bioprospecting.

    Science.gov (United States)

    Xia, Ye; Lei, Lei; Brabham, Chad; Stork, Jozsef; Strickland, James; Ladak, Adam; Gu, Ying; Wallace, Ian; DeBolt, Seth

    2014-01-01

    In plants, cellulose biosynthesis is an essential process for anisotropic growth and therefore is an ideal target for inhibition. Based on the documented utility of small-molecule inhibitors to dissect complex cellular processes we identified a cellulose biosynthesis inhibitor (CBI), named acetobixan, by bio-prospecting among compounds secreted by endophytic microorganisms. Acetobixan was identified using a drug-gene interaction screen to sift through hundreds of endophytic microbial secretions for one that caused synergistic reduction in root expansion of the leaky AtcesA6prc1-1 mutant. We then mined this microbial secretion for compounds that were differentially abundant compared with Bacilli that failed to mimic CBI action to isolate a lead pharmacophore. Analogs of this lead compound were screened for CBI activity, and the most potent analog was named acetobixan. In living Arabidopsis cells visualized by confocal microscopy, acetobixan treatment caused CESA particles localized at the plasma membrane (PM) to rapidly re-localize to cytoplasmic vesicles. Acetobixan inhibited 14C-Glc uptake into crystalline cellulose. Moreover, cortical microtubule dynamics were not disrupted by acetobixan, suggesting specific activity towards cellulose synthesis. Previous CBI resistant mutants such as ixr1-2, ixr2-1 or aegeus were not cross resistant to acetobixan indicating that acetobixan targets a different aspect of cellulose biosynthesis.

  19. Morphological and Thermal Properties of Cellulose Nanofibrils Reinforced Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Deniz Aydemir

    2015-04-01

    Full Text Available Epoxy resins have gained attention as important adhesives because they are structurally stable, inert to most chemicals, and highly resistant to oxidation. Different particles can be added to adhesives to improve their properties. In this study, cellulose nanofibrils (CNFs, which have superior mechanical properties, were used as the reinforcing agent. Cellulose nanofi brils were added to epoxy in quantities of 1 %, 2 % and 3 % by weight to prepare nanocomposites. Morphological characterization of the composites was done with scanning electron microscopy (SEM. Thermal properties of the nanocomposites were investigated with Thermogravimetric Analyzer (TGA/DTG and Differential Scanning Calorimeter (DSC. SEM images showed that the cellulose nanofibrils were dispersed partially homogenous throughout the epoxy matrix for 1 % CNF. However, it was observed that the cellulose nanofibrils were aggregated (especially for 2 and 3 % CNFs in some parts of the SEM images, and the ratios of the aggregated parts increased as the loading rate of the cellulose nanofi brils increased. The TGA curve showed that DTG and decomposition temperature of pure epoxy was higher than that of the nanocomposites. The DSC curve showed that the glass transition temperature (Tg value of pure epoxy was found to be similar with Tg of the nanocomposites.

  20. Preparation of food grade carboxymethyl cellulose from corn husk agrowaste.

    Science.gov (United States)

    Mondal, Md Ibrahim H; Yeasmin, Mst Sarmina; Rahman, Md Saifur

    2015-08-01

    Alpha-cellulose extracted from corn husks was used as the raw material for the production of food-grade carboxymethyl cellulose (CMC). Preparation of CMC from husk cellulose was carried out by an etherification process, using sodium hydroxide and monochloroacetic acid (MCA), with ethanol as the supporting medium. Characterizations of CMC were carried out by analyzing the spectra of FTIR, XRD patterns and SEM photomicrographs. Degree of substitution (DS) was determined with respect to particle size using chemical methods. Solubility, molecular weight and DS of CMC increased with decreased cellulose particle sizes. Microbiological testing of the prepared CMC was done by the pour plate method. Concentrations of heavy metals such as arsenic, lead, cadmium and mercury in the purified CMC were measured by Atomic Absorption Spectroscopy technique and found to be within the WHO/FAO recommended value. A comparative study with CMC available in the international market was conducted. The purity of the prepared CMC was higher, at 99.99% well above the purity of 99.5% for standard CMC. High purity CMC showed a yield 2.4 g/g with DS 2.41, water holding capacity 5.11 g/g, oil holding capacity 1.59 g/g. The obtained product is well suited for pharmaceutical and food additives.

  1. Bacterial cellulose/boehmite composites

    Energy Technology Data Exchange (ETDEWEB)

    Salvi, Denise T.B. de; Barud, Hernane S.; Messaddeq, Younes; Ribeiro, Sidney J.L. [Universidade Estadual Paulista Julio de Mesquita Filho. UNESP. Instituto de Quimica de Araraquara, SP (Brazil); Caiut, Jose Mauricio A. [Universidade de Sao Paulo. Departamento de Quimica - FFCLRP/USP, Ribeirao Preto, SP (Brazil)

    2011-07-01

    Composites based on bacterial cellulose membranes and boehmite were obtained. SEM results indicate that the bacterial cellulose (BC) membranes are totally covered by boehmite and obtained XRD patterns suggest structural changes due to this boehmite addition. Thermal stability is accessed through TG curves and is dependent on boehmite content. Transparency is high comparing to pure BC as can be seen through UV-vis absorption spectroscopy. (author)

  2. Cellulose crystallinity index: measurement techniques and their impact on interpreting cellulase performance.

    Science.gov (United States)

    Park, Sunkyu; Baker, John O; Himmel, Michael E; Parilla, Philip A; Johnson, David K

    2010-05-24

    Although measurements of crystallinity index (CI) have a long history, it has been found that CI varies significantly depending on the choice of measurement method. In this study, four different techniques incorporating X-ray diffraction and solid-state 13C nuclear magnetic resonance (NMR) were compared using eight different cellulose preparations. We found that the simplest method, which is also the most widely used, and which involves measurement of just two heights in the X-ray diffractogram, produced significantly higher crystallinity values than did the other methods. Data in the literature for the cellulose preparation used (Avicel PH-101) support this observation. We believe that the alternative X-ray diffraction (XRD) and NMR methods presented here, which consider the contributions from amorphous and crystalline cellulose to the entire XRD and NMR spectra, provide a more accurate measure of the crystallinity of cellulose. Although celluloses having a high amorphous content are usually more easily digested by enzymes, it is unclear, based on studies published in the literature, whether CI actually provides a clear indication of the digestibility of a cellulose sample. Cellulose accessibility should be affected by crystallinity, but is also likely to be affected by several other parameters, such as lignin/hemicellulose contents and distribution, porosity, and particle size. Given the methodological dependency of cellulose CI values and the complex nature of cellulase interactions with amorphous and crystalline celluloses, we caution against trying to correlate relatively small changes in CI with changes in cellulose digestibility. In addition, the prediction of cellulase performance based on low levels of cellulose conversion may not include sufficient digestion of the crystalline component to be meaningful.

  3. Surface modification of cellulose nanocrystals

    Science.gov (United States)

    Eyley, Samuel; Thielemans, Wim

    2014-06-01

    Chemical modification of cellulose nanocrystals is an increasingly popular topic in the literature. This review analyses the type of cellulose nanocrystal modification reactions that have been published in the literature thus far and looks at the steps that have been taken towards analysing the products of the nanocrystal modifications. The main categories of reactions carried out on cellulose nanocrystals are oxidations, esterifications, amidations, carbamations and etherifications. More recently nucleophilic substitutions have been used to introduce more complex functionality to cellulose nanocrystals. Multi-step modifications are also considered. This review emphasizes quantification of modification at the nanocrystal surface in terms of degree of substitution and the validity of conclusions drawn from different analysis techniques in this area. The mechanisms of the modification reactions are presented and considered with respect to the effect on the outcome of the reactions. While great strides have been made in the quality of analytical data published in the field of cellulose nanocrystal modification, there is still vast scope for improvement, both in data quality and the quality of analysis of data. Given the difficulty of surface analysis, cross-checking of results from different analysis techniques is fundamental for the development of reliable cellulose nanocrystal modification techniques.

  4. Nanomechanics of cellulose crystals and cellulose-based polymer composites

    Science.gov (United States)

    Pakzad, Anahita

    Cellulose-polymer composites have potential applications in aerospace and transportation areas where lightweight materials with high mechanical properties are needed. In addition, these economical and biodegradable composites have been shown to be useful as polymer electrolytes, packaging structures, optoelectronic devices, and medical implants such as wound dressing and bone scaffolds. In spite of the above mentioned advantages and potential applications, due to the difficulties associated with synthesis and processing techniques, application of cellulose crystals (micro and nano sized) for preparation of new composite systems is limited. Cellulose is hydrophilic and polar as opposed to most of common thermoplastics, which are non-polar. This results in complications in addition of cellulose crystals to polymer matrices, and as a result in achieving sufficient dispersion levels, which directly affects the mechanical properties of the composites. As in other composite materials, the properties of cellulose-polymer composites depend on the volume fraction and the properties of individual phases (the reinforcement and the polymer matrix), the dispersion quality of the reinforcement through the matrix and the interaction between CNCs themselves and CNC and the matrix (interphase). In order to develop economical cellulose-polymer composites with superior qualities, the properties of individual cellulose crystals, as well as the effect of dispersion of reinforcements and the interphase on the properties of the final composites should be understood. In this research, the mechanical properties of CNC polymer composites were characterized at the macro and nano scales. A direct correlation was made between: - Dispersion quality and macro-mechanical properties - Nanomechanical properties at the surface and tensile properties - CNC diameter and interphase thickness. Lastly, individual CNCs from different sources were characterized and for the first time size-scale effect on

  5. Eggshell and Bacterial Cellulose Composite Membrane as Absorbent Material in Active Packaging

    Directory of Open Access Journals (Sweden)

    S. Ummartyotin

    2016-01-01

    Full Text Available Bacterial cellulose and eggshell composite was successfully developed. Eggshell was mixed with bacterial cellulose suspension and it was casted as a composite film. CaCO3 derived from eggshell was compared with its commercial availability. It can be noted that good dispersion of eggshell particle was prepared. Eggshell particle was irregular in shape with a variation in size. It existed in bacterial cellulose network. Characterization on composite was focused on thermal and mechanical properties. It showed that flexibility and thermal stability of composite were enhanced. No significant effect of mechanical properties was therefore observed. The thermal stability of composite was stable up to 300°C. The adsorption experiment on water and vegetable oil capacity was performed. The enhancement on adsorption was due to the existence of eggshell in bacterial cellulose composite. It exhibited the potential to be a good candidate for absorbent material in active packaging.

  6. Functionalization of Recombinant Amelogenin Nanospheres Allows Their Binding to Cellulose Materials.

    Science.gov (United States)

    Butler, Samuel J; Bülow, Leif; Bonde, Johan

    2016-10-01

    Protein engineering to functionalize the self-assembling enamel matrix protein amelogenin with a cellulose binding domain (CBD) is used. The purpose is to examine the binding of the engineered protein, rh174CBD, to cellulose materials, and the possibility to immobilize self-assembled amelogenin nanospheres on cellulose. rh174CBD assembled to nanospheres ≈35 nm in hydrodynamic diameter, very similar in size to wild type amelogenin (rh174). Uniform particles are formed at pH 10 for both rh174 and rh174CBD, but only rh174CBD nanospheres showes significant binding to cellulose (Avicel). Cellulose binding of rh174CBD is promoted when the protein is self-assembled to nanospheres, compared to being in a monomeric form, suggesting a synergistic effect of the multiple CBDs on the nanospheres. The amount of bound rh174CBD nanospheres reached ≈15 mg/g Avicel, which corresponds to 4.2 to 6.3 × 10(-7) mole/m(2) . By mixing rh174 and rh174CBD, and then inducing self-assembly, composite nanospheres with a high degree of cellulose binding can be formed, despite a lower proportion of rh174CBD. This demonstrates that amelogenin variants like rh174 can be incorporated into the nanospheres, and still retain most of the binding to cellulose. Engineered amelogenin nanoparticles can thus be utilized to construct a range of new cellulose based hybrid materials, e.g. for wound treatment.

  7. Ionic liquid processing of cellulose.

    Science.gov (United States)

    Wang, Hui; Gurau, Gabriela; Rogers, Robin D

    2012-02-21

    Utilization of natural polymers has attracted increasing attention because of the consumption and over-exploitation of non-renewable resources, such as coal and oil. The development of green processing of cellulose, the most abundant biorenewable material on Earth, is urgent from the viewpoints of both sustainability and environmental protection. The discovery of the dissolution of cellulose in ionic liquids (ILs, salts which melt below 100 °C) provides new opportunities for the processing of this biopolymer, however, many fundamental and practical questions need to be answered in order to determine if this will ultimately be a green or sustainable strategy. In this critical review, the open fundamental questions regarding the interactions of cellulose with both the IL cations and anions in the dissolution process are discussed. Investigations have shown that the interactions between the anion and cellulose play an important role in the solvation of cellulose, however, opinions on the role of the cation are conflicting. Some researchers have concluded that the cations are hydrogen bonding to this biopolymer, while others suggest they are not. Our review of the available data has led us to urge the use of more chemical units of solubility, such as 'g cellulose per mole of IL' or 'mol IL per mol hydroxyl in cellulose' to provide more consistency in data reporting and more insight into the dissolution mechanism. This review will also assess the greenness and sustainability of IL processing of biomass, where it would seem that the choices of cation and anion are critical not only to the science of the dissolution, but to the ultimate 'greenness' of any process (142 references).

  8. Fluid mechanics relevant to flow through pretreatment of cellulosic biomass.

    Science.gov (United States)

    Archambault-Léger, Véronique; Lynd, Lee R

    2014-04-01

    The present study investigates fluid mechanical properties of cellulosic feedstocks relevant to flow through (FT) pretreatment for biological conversion of cellulosic biomass. The results inform identifying conditions for which FT pretreatment can be implemented in a practical context. Measurements of pressure drop across packed beds, viscous compaction and water absorption are reported for milled and not milled sugarcane bagasse, switchgrass and poplar, and important factors impacting viscous flow are deduced. Using biomass knife-milled to pass through a 2mm sieve, the observed pressure drop was highest for bagasse, intermediate for switchgrass and lowest for poplar. The highest pressure drop was associated with the presence of more fine particles, greater viscous compaction and the degree of water absorption. Using bagasse without particle size reduction, the instability of the reactor during pretreatment above 140kg/m(3) sets an upper bound on the allowable concentration for continuous stable flow.

  9. Synthesis, characterization, and reactivity of cellulose modified nano zero-valent iron for dye discoloration

    Science.gov (United States)

    Wang, Xiangyu; Wang, Pei; Ma, Jun; Liu, Huiling; Ning, Ping

    2015-08-01

    Nano zero-valent iron (NZVI) was innovatively and successfully modified by using hydroxyethyl cellulose (HEC) and hydroxypropylmethyl cellulose (HPMC) as dispersants. The systematic characterization observations (including XRD, SEM and TEM) illustrate that, compared with bare nano zero-valent iron particles (BNZVI), the particle sizes of hydroxyethyl cellulose modified (ENZVI) and hydroxypropylmethyl cellulose modified (PNZVI) were decreased, while the dispersity and antioxidizability of ENZVI and PNZVI particles were increased. The discoloration efficiencies of ENZVI, PNZVI, and BNZVI were compared by using dyes (including orange II, methyl orange, methyl blue, and methylene blue) as target pollutant. The results show that both the discoloration efficiency and reaction rate of ENZVI and PNZVI are higher than that of BNZVI. In addition, effects of dispersant content, dye type, pH value, initial dye concentration, iron dosage, and reaction temperature on discoloration efficiencies were studied. The results show that discoloration efficiency was decreased by increasing initial pH value and dye concentration, and it was increased with the increase the iron dosage and reaction temperature. Under optimized NZVI addition of 0.7 g L-1, the discoloration efficiencies of ENZVI and PNZVI were increased to 96.33% and 98.62%, respectively. And the possible discoloration pathway and dispersant modification mechanism of NZVI were discussed. This study suggests hydroxyethyl cellulose and hydroxypropylmethyl cellulose dispersed NZVI can be utilized as a promising modified nano-material for degradation of dye wastewater.

  10. A METHOD OF PREPARING SPHERICAL NANO-CRYSTAL CELLULOSE WITH MIXED CRYSTALLINE FORMS OF CELLULOSE Ⅰ AND Ⅱ

    Institute of Scientific and Technical Information of China (English)

    Xiao-fang Li; En-yong Ding; Guo-kang Li

    2001-01-01

    A new kind of nano-crystal cellulose (NCC) prepared from natural cotton fiber has been obtained by the method of acid hydrolysis. Compared to most other nanophase materials that derive from inorganic materials, our products are prepared from natural cotton fibers. The products are of spherical shape with mixed crystal forms of cellulose Ⅰ and Ⅱ. The preparation conditions determine the properties of the products. Prior treatment is a critical procedure. The properties of the products are also strongly affected by such conditions as the kinds of acids used, the ratio of the acid mixture, the acid concentration, the ultrasonic agitation time and hydrolysis temperature. The number average molecular weight of NCC is determined by gel permeation chromatography (GPC). The particle size and shape were determined by transmission electron microscopy (TEM). X-ray diffraction was used to detect the crystallinity and average crystallite size of the particle.

  11. SIZE EXCLUSION CHROMATOGRAPHIC COLUMN PACKED WITH REGENERATED CELLULOSE GELS

    Institute of Scientific and Technical Information of China (English)

    Guang Yang; Li-na Zhang; Xiao-peng Xiong; Xiao-dong Cao; Yong-liang Yang

    2001-01-01

    Microporous regenerated cellulose gel particles were prepared by mixing cellulose cuoxam with silk fibroin as pore former, and the mean pore size and pore volume of the particles were 525 nm and 7.27 mL g-1, respectively. A preparative size-exclusion chromatography (SEC) column (550 mm × 20 mm) packed with the cellulose gel particles was used for the fractionation of two polysaccharides Dextran 07 (Mw=7.14×104, d = 1.7) and Dextran 50 (Mw = 50.5×104,d = 3.8) in water phase. The fractionation range of the stationary phase covered Mw from 3 × 103 to 1.1 × 106. The daily throughput was 2.9 g for Dextran 07 (D07) and 4.3 g for Dextran 50 (D50) with a flow-rate of 1.5 mL min-1. The fractions obtained by using the SEC were analyzed by an analytical SEC combined with laser light scattering (LLS), and the polydispersity indices of fractions for Dextran 07 and Dextran 50 were determined to be 1.34-1.57 and 1.53-3.36,respectively. The preparative SEC is a simple, rapid, and suitable means not only for the fractionation of polysaccharides in water but also for other polymers in organic solvents.``

  12. Cellulose nanocrystal reinforced oxidized natural rubber nanocomposites.

    Science.gov (United States)

    Mariano, Marcos; El Kissi, Nadia; Dufresne, Alain

    2016-02-10

    Natural rubber (NR) latex particles were oxidized using KMnO4 as oxidant to promote the insertion of hydroxyl groups in the surface polyisoprene chains. Different degrees of oxidation were investigated. Both unoxidized and oxidized NR (ONR) latex were used to prepare nanocomposite films reinforced with cellulose nanocrystals (CNCs) by casting/evaporation. The oxidation of NR was carried out to promote chemical interactions between the hydroxyl groups of ONR with those of CNCs through hydrogen bonding. The effect of the degree of oxidation of the NR latex on the rheological behavior of CNC/NR and CNC/ONR suspensions, as well as on the mechanical, swelling and thermal properties of ensuing nanocomposites was investigated. Improved properties were observed for intermediate degrees of oxidation but they were found to degrade for higher oxidation levels.

  13. Plant cellulose synthesis: CESA proteins crossing kingdoms.

    Science.gov (United States)

    Kumar, Manoj; Turner, Simon

    2015-04-01

    Cellulose is a biopolymer of considerable economic importance. It is synthesised by the cellulose synthase complex (CSC) in species ranging from bacteria to higher plants. Enormous progress in our understanding of bacterial cellulose synthesis has come with the recent publication of both the crystal structure and biochemical characterisation of a purified complex able to synthesis cellulose in vitro. A model structure of a plant CESA protein suggests considerable similarity between the bacterial and plant cellulose synthesis. In this review article we will cover current knowledge of how plant CESA proteins synthesise cellulose. In particular the focus will be on the lessons learned from the recent work on the catalytic mechanism and the implications that new data on cellulose structure has for the assembly of CESA proteins into the large complex that synthesis plant cellulose microfibrils.

  14. Characterization of Cellulose Synthesis in Plant Cells

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Maleki

    2016-01-01

    Full Text Available Cellulose is the most significant structural component of plant cell wall. Cellulose, polysaccharide containing repeated unbranched β (1-4 D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC from bacteria to plants. The CSC is involved in biosynthesis of cellulose microfibrils containing 18 cellulose synthase (CesA proteins. Macrofibrils can be formed with side by side arrangement of microfibrils. In addition, beside CesA, various proteins like the KORRIGAN, sucrose synthase, cytoskeletal components, and COBRA-like proteins have been involved in cellulose biosynthesis. Understanding the mechanisms of cellulose biosynthesis is of great importance not only for improving wood production in economically important forest trees to mankind but also for plant development. This review article covers the current knowledge about the cellulose biosynthesis-related gene family.

  15. Development of nonflammable cellulosic foams

    Science.gov (United States)

    Luttinger, M.

    1972-01-01

    The development of a moldable cellulosic foam for use in Skylab instrument storage cushions is considered. Requirements include density of 10 lb cu ft or less, minimal friability with normal handling, and nonflammability in an atmosphere of 70 percent oxygen and 30 percent nitrogen at 6.2 psia. A study of halogenated foam components was made, including more highly chlorinated binders, halogen-containing additives, and halogenation of the cellulose. The immediate objective was to reduce the density of the foam through reduction in inorganic phosphate without sacrificing flame-retarding properties of the foams. The use of frothing techniques was investigated, with particular emphasis on a urea-formaldehyde foam. Halogen-containing flame retardants were deemphasized in favor of inorganic salts and the preparation of phosphate and sulphate esters of cellulose. Utilization of foam products for civilian applications was also considered.

  16. Biocompatibility of Bacterial Cellulose Based Biomaterials

    OpenAIRE

    2012-01-01

    Some bacteria can synthesize cellulose when they are cultivated under adequate conditions. These bacteria produce a mat of cellulose on the top of the culture medium, which is formed by a three-dimensional coherent network of pure cellulose nanofibers. Bacterial cellulose (BC) has been widely used in different fields, such as the paper industry, electronics and tissue engineering due to its remarkable mechanical properties, conformability and porosity. Nanocomposites based on BC have received...

  17. Characterization of Epoxy Composites Reinforced with Wax Encapsulated Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Yuanfeng Pan

    2016-11-01

    Full Text Available The effect of paraffin wax encapsulated microcrystalline cellulose (EMC particles on the mechanical and physical properties of EMC/epoxy composites were investigated. It was demonstrated that the compatibility between cellulose and epoxy resin could be maintained due to partial encapsulation resulting in an improvement in epoxy composite mechanical properties. This work was unique because it was possible to improve the physical and mechanical properties of the EMC/epoxy composites while encapsulating the microcrystalline cellulose (MCC for a more homogeneous dispersion. The addition of EMC could increase the stiffness of epoxy composites, especially when the composites were wet. The 1% EMC loading with a 1:2 ratio of wax:MCC demonstrated the best reinforcement for both dry and wet properties. The decomposition temperature of epoxy was preserved up to a 5% EMC loading and for different wax:MCC ratios. An increase in wax encapsulated cellulose loading did increase water absorption but overall this absorption was still low (<1% for all composites.

  18. Ultrasound influence upon calcium carbonate precipitation on bacterial cellulose membranes.

    Science.gov (United States)

    Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin; Jipa, Iuliana; Dobre, Tanase; Dobre, Loredana

    2012-07-01

    The effect of ultrasonic irradiation (40 kHz) on the calcium carbonate deposition on bacterial cellulose membranes was investigated using calcium chloride (CaCl(2)) and sodium carbonate (Na(2)CO(3)) as starting reactants. The composite materials containing bacterial cellulose-calcium carbonate were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and color measurements. The polymorphs of calcium carbonate that were deposited on bacterial cellulose membranes in the presence or in the absence of ultrasonic irradiation were calcite and vaterite. The morphology of the obtained crystals was influenced by the concentration of starting solutions and by the presence of ultrasonic irradiation. In the presence of ultrasonic irradiation the obtained crystals were bigger and in a larger variety of shapes than in the absence of ultrasounds: from cubes of calcite to spherical and flower-like vaterite particles. Bacterial cellulose could be a good matrix for obtaining different types of calcium carbonate crystals.

  19. The trafficking and behavior of cellulose synthase and a glimpse of potential cellulose synthesis regulators

    Institute of Scientific and Technical Information of China (English)

    Logan BASHLINE; Juan DU; Ying GU

    2011-01-01

    Cellulose biosynthesis is a topic of intensive research not only due to the significance of cellulose in the integrity of plant cell walls,but also due to the potential of using cellulose,a natural carbon source,in the production ot biofuels.Characterization of the composition,regulation,and trafficking of cellulose synthase complexes (CSCs) is critical to an understanding of cellulose biosynthesis as well as the characterization of additional proteins that contribute to the production of cellulose either through direct interactions with CSCs or through indirect mechanisms.In this review,a highlight of a few proteins that appear to affect cellulose biosynthesis,which includes:KORRIGAN (KOR),Cellulose Synthase-Interactive Protein 1 (CSI1),and the poplar microtubule-associated protein,PttMAP20,will accompany a description of cellulose synthase (CESA) behavior and a discussion of CESA trafficking compartments that might act in the regulation of cellulose biosynthesis.

  20. Bioengineering cellulose-hemicellulose networks in plants

    NARCIS (Netherlands)

    Obembe, O.

    2006-01-01

    The interactions between cellulose and hemicellulose in the cell walls are important in the industrial application of the cellulose (natural) fibres. We strive to modify these interactions (i) by interfering with cellulose biosynthesis and (ii) by direct interference of the

  1. Adsorption and desorption of cellulose derivatives.

    NARCIS (Netherlands)

    Hoogendam, C.W.

    1998-01-01

    Cellulose derivatives, in particular carboxymethyl cellulose (CMC) are used in many (industrial) applications. The aim of this work is to obtain insight into the adsorption mechanism of cellulose derivatives on solid-liquid interfaces.In chapter 1 of this thesis we discuss some appl

  2. Atomic force microscopy study of cellulose surface interaction controlled by cellulose binding domains

    OpenAIRE

    Nigmatullin, R.; Lovitt, R.; Wright, C; Linder, M.; Nakari-Setälä, T; Gama, F. M.

    2004-01-01

    Colloidal probe microscopy has been used to study the interaction between model cellulose surfaces and the role of cellulose binding domain (CBD), peptides specifically binding to cellulose, in interfacial interaction of cellulose surfaces modified with CBDs. The interaction between pure cellulose surfaces in aqueous electrolyte solution is dominated by double layer repulsive forces with the range and magnitude of the net force dependent on electrolyte concentration. AFM imaging reve...

  3. Physicotechnical, spectroscopic and thermogravimetric properties of powdered cellulose and microcrystalline cellulose derived from groundnut shells

    OpenAIRE

    Chukwuemeka P. Azubuike; Jimson O. Odulaja; Augustine O Okhamafe

    2012-01-01

    α-Cellulose and microcrystalline cellulose powders, derived from agricultural waste products, that have for thepharmaceutical industry, desirable physical (flow) properties were investigated. α–Cellulose (GCN) wasextracted from groundnut shell (an agricultural waste product) using a non-dissolving method based oninorganic reagents. Modification of this α -cellulose was carried out by partially hydrolysing it with 2Nhydrochloric acid under reflux to obtain microcrystalline cellulose (MCGN). Th...

  4. Impact of Biofield Treatment on Chemical and Thermal Properties of Cellulose and Cellulose Acetate

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Cellulose being an excellent biopolymer has cemented its place firmly in many industries as a coating material, textile, composites, and biomaterial applications. In the present study, we have investigated the effect of biofield treatment on physicochemical properties of cellulose and cellulose acetate. The cellulose and cellulose acetate were exposed to biofield and further the chemical and thermal properties were investigated. X-ray diffraction study asserted that the biofield treatment did...

  5. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  6. Preparation and characterization of nano-cellulose with new shape from different precursor.

    Science.gov (United States)

    Maiti, Sonakshi; Jayaramudu, J; Das, Kunal; Reddy, Siva Mohan; Sadiku, Rotimi; Ray, Suprakas Sinha; Liu, Dagang

    2013-10-15

    Three different precursor materials - 1. China cotton, 2. South African cotton, 3. Waste tissue papers were used to produce nano-cellulose by acid hydrolysis route. No chemical pretreatment has been done for the production of nano-cellulose from these precursors. Prepared nano-cellulose and their corresponding precursor materials were characterized by transmission electron microscopy (TEM), particle size analysis, X-ray diffraction (XRD) study, thermo gravimetric analysis (TGA), differential scanning calorimetric (DSC) analysis and Fourier transformed infra red (FTIR) spectroscopy. A comparative study of the characteristics was done with the properties of raw materials and with that of nano-cellulose. Shape and size of the nano cellulose generally depends on nature of the precursor and hydrolysis condition. Morphology study of nano-cellulose from different sources revealed range of length from 50 to 200 nm and diameter from 10 to 90 nm. Higher thermal stability and crystallinity of nano-cellulose were observed compared to that of precursor from TGA/DSC study.

  7. Foaming of Ethyl Hydroxyethyl Cellulose

    OpenAIRE

    Carrillo Agilera, Marc

    2015-01-01

    The current depletion of petroleum resources together with environmental issues have led to new approaches in plastic manufacturing. This trend involves using ecofriendly materials coming from renewable resources. Good candidates for this, due to their properties and availability, are the cellulose derivatives. Some of them, such as hydroxypropyl methylcellulose (HPMC), showed in previous studies a promising behavior when making polymeric foams. Unfortunately, the corresponding...

  8. Controlled Silylation of Nanofibrillated Cellulose in Water: Reinforcement of a Model Polydimethylsiloxane Network.

    Science.gov (United States)

    Zhang, Zheng; Tingaut, Philippe; Rentsch, Daniel; Zimmermann, Tanja; Sèbe, Gilles

    2015-08-24

    A comparative approach for the surface silylation of nanofibrillated cellulose (NFC) in water is proposed through an environmentally friendly sol-gel route based on alkoxysilanes. NFC suspensions were freeze-dried under controlled conditions in the presence of methyltrimethoxysilane used as a model alkoxysilane. Two different protocols that involve different pH values (0.4 and 4) and post-treatment procedures were investigated and compared. Protocol 1 led to a network of nanofibrils in which polysiloxane particles were dispersed, and protocol 2 produced a scaffold of cellulosic fibrils coated by a polysiloxane layer bonded firmly to the cellulosic substrate. Different from protocol 1, protocol 2 imparted the cellulosic material with hydrophobic properties and improved its thermal stability. Moreover, if 1 wt % of fibrils treated by protocol 2 were incorporated into a model polydimethylsiloxane network, substantial improvements of the static and dynamic mechanical properties of the composite were noted.

  9. Cellulose nanomaterials in water treatment technologies.

    Science.gov (United States)

    Carpenter, Alexis Wells; de Lannoy, Charles-François; Wiesner, Mark R

    2015-05-05

    Cellulose nanomaterials are naturally occurring with unique structural, mechanical and optical properties. While the paper and packaging, automotive, personal care, construction, and textiles industries have recognized cellulose nanomaterials' potential, we suggest cellulose nanomaterials have great untapped potential in water treatment technologies. In this review, we gather evidence of cellulose nanomaterials' beneficial role in environmental remediation and membranes for water filtration, including their high surface area-to-volume ratio, low environmental impact, high strength, functionalizability, and sustainability. We make direct comparison between cellulose nanomaterials and carbon nanotubes (CNTs) in terms of physical and chemical properties, production costs, use and disposal in order to show the potential of cellulose nanomaterials as a sustainable replacement for CNTs in water treatment technologies. Finally, we comment on the need for improved communication and collaboration across the myriad industries invested in cellulose nanomaterials production and development to achieve an efficient means to commercialization.

  10. Effect of the chemical treatments on the characteristics of natural cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Sosiati, H., E-mail: hsosiati@ugm.ac.id [Nanomaterials Research Group, Integrated Research and Testing Laboratory (LPPT), Gadjah Mada University, Yogyakarta 55281 (Indonesia); Muhaimin, M.; Abdilah, P.; Wijayanti, D. A. [Department of Physics, Faculty of Mathematics and Natural of Sciences, Gadjah Mada University, Yogyakarta 55281 (Indonesia); Harsojo; Triyana, K. [Nanomaterials Research Group, Integrated Research and Testing Laboratory (LPPT), Gadjah Mada University, Yogyakarta 55281, Indonesia and Department of Physics, Faculty of Mathematics and Natural of Sciences, Gadjah Mada University, Yogyakarta 55281 (Indonesia)

    2014-09-25

    In order to characterize the morphology and size distribution of the cellulose fibers, natural cellulose from kenaf bast fibers was extracted using two chemical treatments; (1) alkali-bleaching-ultrasonic treatment and (2) alkali-bleaching-hydrolysis. Solutions of NaOH, H{sub 2}O{sub 2} and H{sub 2}SO{sub 4} were used for alkalization, bleaching and hydrolysis, respectively. The hydrolyzed fibers were centrifuged at a rotation speed of 10000 rpm for 10 min to separate the nanofibers from the microfibers. The separation was repeated in 7 steps by controlling pH of the solution in each step until neutrality was reached. Fourier transform infrared (FTIR) spectroscopy was performed on the fibers at the final step of each treatment: i.e. either ultrasonic treated- or hydrolyzed microfibers. Their FTIR spectra were compared with FTIR spectrum of a reference commercial α-cellulose. Changes in morphology and size distribution of the treated fibers were examined by scanning electron microscopy (SEM). FTIR spectra of ultrasonic treated- and hydrolyzed microfibers nearly coincided with the FTIR spectrum of commercial α-cellulose, suggesting successful extraction of cellulose. Ultrasonic treatment for 6 h resulted in a specific morphology in which cellulose nanofibers (≥100 nm) were distributed across the entire surface of cellulose microfibers (∼5 μm). Constant magnetic stirring combined with acid hydrolysis resulted in an inhomogeneous size distribution of both cellulose rods (500 nm-3 μm length, 100–200 nm diameter) and particles 100–200 nm in size. Changes in morphology of the cellulose fibers depended upon the stirring time; longer stirring time resulted in shorter fiber lengths.

  11. Oxidized Cellulose with Different Carboxyl Content: Structure and Properties before and after Beating

    Science.gov (United States)

    Vendula, Hejlová; Miloslav, Milichovský

    Our recent studies concentrated in investigating influence of beating oxidized cellulose, with different carboxyl content, on changing their basic properties (degree of polymerization, WRV - water resistant value and X-ray diffraction). Cellulose samples of oxidized cellulose were beated by toroidal beating machine. Cellulose consists of both amorphous and crystalline regions. Cellulose consists of linear chains of poly[ß-1,4-D- anhydroglucopyranose] (C6nH10n + 2O5n + 1 (n = degree of polymerization of glucose)), which crystallize through hydrogen bonding between the chains and has cellobiose as repeat unit. Oxidized cellulose is preparing by oxidation of cellulose in the C6 position of the glucopyranose units to carboxylic group (-COOH) and polyanhydroglukuronic acid (PAGA) is arised. An other option is oxidation with sodium hypochlorite with catalytic amounts of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) under various conditions. Beating and refining or mechanical treatment of fibers in water is an important step in using pulps for papermaking. It is an energy intensive process. The purpose of the treatment is to modify fiber properties to obtain the most desirable paper machine runnability and product properties. End of beating pulps was characterized by position, when all beated pulps under mixture passed through of riddle (about sizes mesh of 50). During beating of samples about different ratio of oxidation it was found, that samples with higher contents of COOH groups in starting pulp are characterized by a significantly lower specific beating energy consumption needed to achieving the same sizes of particles. X-ray analyse shows that for non-beated oxidized cellulose was perceptible high share amorphous contents compared with beated oxidized cellulose.

  12. Study on the Preparation and Characteristics of Cellulose/Silver Iodide Nanocomposite Film.

    Science.gov (United States)

    Lee, Yang Hun; Han, Sung Soo; Kang, Young Ah; Shin, Eun Joo

    2016-06-01

    In this study, the structure and properties of an organic-inorganic composite material prepared from cellulose doped with fine particles of silver iodide (AgI) were examined. The preparation of the composite involved the complexation of cellulose with polyiodide ions, such as I- and 13-, by immersion in iodine/potassium iodide (I2/KI: 0.2, 0.4, 0.6, 0.8, 1.0 M) or potassium iodide (KI: 0.6, 1.2, 1.8, 2.4, 3.0 M) aqueous solutions followed by reaction in a silver nitrate (AgNO3:1.0 M) aqueous solution. These procedures resulted in the in situ formation of fine β-AgI particles within the cellulose matrix. The characteristics and conductivities of prepared cellulose/silver iodide (AgI) nanocomposite films with different I2/KI and KI concentrations were investigated. AgI particle formation and aggregation increased on increasing I2/KI and KI concentrations as determined by SEM. X-ray results showed that KI could penetrate the cellulose crystal region and form AgI particles. The electrical conductivities of nanocomposite films treated with KI were higher than that of I2/KI at < 1.0 M of I2/KI and 3 M of KI, although the weight gain by AgI formation was lower than that of I2/KI. This was also attributed to the formation of smaller AgI particles and crystal defects. Highest electrical conductivity (3.8 x 10(-7) Ω(-1) cm(-1)) was obtained from the cellulose films (1.25 x 10(-11) Ω(-1) cm(-1)) treated with the aqueous solutions of 1.0 M I2/KI and 1.0 M AgNO3.

  13. Copper removal using electrosterically stabilized nanocrystalline cellulose.

    Science.gov (United States)

    Sheikhi, Amir; Safari, Salman; Yang, Han; van de Ven, Theo G M

    2015-06-03

    Removal of heavy metal ions such as copper using an efficient and low-cost method with low ecological footprint is a critical process in wastewater treatment, which can be achieved in a liquid phase using nanoadsorbents such as inorganic nanoparticles. Recently, attention has turned toward developing sustainable and environmentally friendly nanoadsorbents to remove heavy metal ions from aqueous media. Electrosterically stabilized nanocrystalline cellulose (ENCC), which can be prepared from wood fibers through periodate/chlorite oxidation, has been shown to have a high charge content and colloidal stability. Here, we show that ENCC scavenges copper ions by different mechanisms depending on the ion concentration. When the Cu(II) concentration is low (C0≲200 ppm), agglomerates of starlike ENCC particles appear, which are broken into individual starlike entities by shear and Brownian motion, as evidenced by photometric dispersion analysis, dynamic light scattering, and transmission electron microscopy. On the other hand, at higher copper concentrations, the aggregate morphology changes from starlike to raftlike, which is probably due to the collapse of protruding dicarboxylic cellulose (DCC) chains and ENCC charge neutralization by copper adsorption. Such raftlike structures result from head-to-head and lateral aggregation of neutralized ENCCs as confirmed by transmission electron microscopy. As opposed to starlike aggregates, the raftlike structures grow gradually and are prone to sedimentation at copper concentrations C0≳500 ppm, which eliminates a costly separation step in wastewater treatment processes. Moreover, a copper removal capacity of ∼185 mg g(-1) was achieved thanks to the highly charged DCC polyanions protruding from ENCC. These properties along with the biorenewability make ENCC a promising candidate for wastewater treatment, in which fast, facile, and low-cost removal of heavy metal ions is desired most.

  14. Cellulose nanocrystal submonolayers by spin coating.

    Science.gov (United States)

    Kontturi, Eero; Johansson, Leena-Sisko; Kontturi, Katri S; Ahonen, Päivi; Thüne, Peter C; Laine, Janne

    2007-09-11

    Dilute concentrations of cellulose nanocrystal solutions were spin coated onto different substrates to investigate the effect of the substrate on the nanocrystal submonolayers. Three substrates were probed: silica, titania, and amorphous cellulose. According to atomic force microscopy (AFM) images, anionic cellulose nanocrystals formed small aggregates on the anionic silica substrate, whereas a uniform two-dimensional distribution of nanocrystals was achieved on the cationic titania substrate. The uniform distribution of cellulose nanocrystal submonolayers on titania is an important factor when dimensional analysis of the nanocrystals is desired. Furthermore, the amount of nanocrystals deposited on titania was multifold in comparison to the amounts on silica, as revealed by AFM image analysis and X-ray photoelectron spectroscopy. Amorphous cellulose, the third substrate, resulted in a somewhat homogeneous distribution of the nanocrystal submonolayers, but the amounts were as low as those on the silica substrate. These differences in the cellulose nanocrystal deposition were attributed to electrostatic effects: anionic cellulose nanocrystals are adsorbed on cationic titania in addition to the normal spin coating deposition. The anionic silica surface, on the other hand, causes aggregation of the weakly anionic cellulose nanocrystals which are forced on the repulsive substrate by spin coating. The electrostatically driven adsorption also influences the film thickness of continuous ultrathin films of cellulose nanocrystals. The thicker films of charged nanocrystals on a substrate of opposite charge means that the film thickness is not independent of the substrate when spin coating cellulose nanocrystals in the ultrathin regime (<100 nm).

  15. New application of crystalline cellulose in rubber composites

    Science.gov (United States)

    Bai, Wen

    the rubber matrix during the vulcanization. Both A-MCC and AnKD-MCC facilitated the process and production of rubber composites and improved tensile properties and heat resistance of the resulting rubber composites as MCC did when they were used for the partial replacement of silica in rubber composites. Furthermore, A-MCC and AnKD-MCC were superior to MCC in terms of improving tear properties of rubber composites. It has been well-established that the size and the geometrical features of reinforcing fillers play important roles in the mechanical properties of the reinforced composites. MCC was further hydrolyzed with acid to form nanocrystalline cellulose (NCC), i.e., cellulose crystals with their width of less than 100 nm. A novel differential centrifugation technique has been developed for separation of NCC mixtures into fractions with a narrow size distribution. The NCC was investigated as a filler in rubber composites through a dry blending process, but saw little success. NCC had to be dried before it could be blended with rubbers. However, NCC particles tended to aggregate after drying and could not be uniformly dispersed into the rubber matrix during the dry blending. As a result, NCC had poor reinforcing effect on rubbers. For future research, the mixing of aqueous suspension of NCC and rubber latex may improve the dispersion of NCC particles in rubbers, thus improving the reinforcing effects of NCC in rubbers.

  16. Polyimide Cellulose Nanocrystal Composite Aerogels

    Science.gov (United States)

    Nguyen, Baochau N.; Meador, Mary Ann; Rowan, Stuart; Cudjoe, Elvis; Sandberg, Anna

    2014-01-01

    Polyimide (PI) aerogels are highly porous solids having low density, high porosity and low thermal conductivity with good mechanical properties. They are ideal for various applications including use in antenna and insulation such as inflatable decelerators used in entry, decent and landing operations. Recently, attention has been focused on stimuli responsive materials such as cellulose nano crystals (CNCs). CNCs are environmentally friendly, bio-renewable, commonly found in plants and the dermis of sea tunicates, and potentially low cost. This study is to examine the effects of CNC on the polyimide aerogels. The CNC used in this project are extracted from mantle of a sea creature called tunicates. A series of polyimide cellulose nanocrystal composite aerogels has been fabricated having 0-13 wt of CNC. Results will be discussed.

  17. CELLULOSE DEGRADATION BY OXIDATIVE ENZYMES

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  18. Flexible Photonic Cellulose Nanocrystal Films

    OpenAIRE

    Guidetti, G.; Atifi, S; Vignolini, S; Hamad, WY

    2016-01-01

    The fabrication of self-assembled cellulose nanocrystal (CNC) films of tunable photonic and mechanical properties using a facile, green approach is demonstrated. The combination of tunable flexibility and iridescence can dramatically expand CNC coating and film barrier capabilities for paints and coating applications, sustainable consumer packaging products, as well as effective templates for photonic and optoelectronic materials and structures. CelluForce Inc., Biotechnology and Biologica...

  19. Preparation of 14C Radiolabelled Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    CHEN; Bao-jun; YANG; Hong-wei; LI; Shuai

    2013-01-01

    Carboxymethyl cellulose(CMC)is a kind of cellulose derivative.CMC has wide applications,including food,daily chemicals,pharmaceutical industry and chemical industry,etc.In order to study the metabolism of CMC,the sodium carboxymethyl cellulose was labelled with 14C.The carboxymethyl cellulose was labelled with 14C by treatment with alkalized cellulose and 14C-

  20. Effects of reaction conditions on cellulose structures synthesized in vitro by bacterial cellulose synthases.

    Science.gov (United States)

    Penttilä, Paavo A; Sugiyama, Junji; Imai, Tomoya

    2016-01-20

    Cellulose was synthesized by cellulose synthases extracted from the Komagataeibacter xylinus (formerly known as Gluconacetobacter xylinus). The effects of temperature and centrifugation of the reaction solution on the synthesis products were investigated. Cellulose with number-average degree of polymerization (DPn) roughly in the range 60-80 and cellulose II crystal structure was produced under all conditions. The amount of cellulose varied with temperature and centrifugation, and the centrifugation at 2000 × g also slightly reduced the DPn. Cellulose production was maximal around the temperature 35 °C and without centrifugation. At higher temperatures and during centrifugation at 2000 × g the proteins started to denature, causing differences also in the morphology of the cellulosic aggregates, as seen with electron microscopy. These observations serve as a basis for discussions about the factors affecting the structure formation and chain length of in vitro synthesized cellulose.

  1. Cellulose Synthases and Synthesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Anne Endler; Staffan Persson

    2011-01-01

    Plant cell walls are complex structures composed of high-molecular-weight polysaccharides,proteins,and lignins. Among the wall polysaccharides,cellulose,a hydrogen-bonded β-1,4-linked glucan microfibril,is the main load-bearing wall component and a key precursor for industrial applications. Cellulose is synthesized by large multi-meric cellulose synthase (CesA) complexes,tracking along cortical microtubules at the plasma membrane. The only known components of these complexes are the cellulose synthase proteins. Recent studies have identified tentative interaction partners for the CesAs and shown that the migratory patterns of the CesA complexes depend on phosphorylation status. These advances may become good platforms for expanding our knowledge about cellulose synthesis in the near future. In addition,our current understanding of cellulose chain polymerization in the context of the CesA complex is discussed.

  2. Assessment of solvents for cellulose dissolution.

    Science.gov (United States)

    Ghasemi, Mohammad; Tsianou, Marina; Alexandridis, Paschalis

    2017-03-01

    A necessary step in the processing of biomass is the pretreatment and dissolution of cellulose. A good solvent for cellulose involves high diffusivity, aggressiveness in decrystallization, and capability of disassociating the cellulose chains. However, it is not clear which of these factors and under what conditions should be improved in order to obtain a more effective solvent. To this end, a newly-developed phenomenological model has been applied to assess the controlling mechanism of cellulose dissolution. Among the findings, the cellulose fibers remain crystalline almost to the end of the dissolution process for decrystallization-controlled kinetics. In such solvents, decreasing the fiber crystallinity, e.g., via pretreatment, would result in a considerable increase in the dissolution rate. Such insights improve the understanding of cellulose dissolution and facilitate the selection of more efficient solvents and processing conditions for biomass. Specific examples of solvents are provided where dissolution is limited due to decrystallization or disentanglement.

  3. Drag Reduction of Bacterial Cellulose Suspensions

    Directory of Open Access Journals (Sweden)

    Satoshi Ogata

    2011-01-01

    Full Text Available Drag reduction due to bacterial cellulose suspensions with small environmental loading was investigated. Experiments were carried out by measuring the pressure drop in pipe flow. It was found that bacterial cellulose suspensions give rise to drag reduction in the turbulent flow range. We observed a maximum drag reduction ratio of 11% and found that it increased with the concentration of the bacterial cellulose suspension. However, the drag reduction effect decreased in the presence of mechanical shear.

  4. Size Effects of Nano-crystalline Cellulose

    Institute of Scientific and Technical Information of China (English)

    Guo Kang LI; Xiao Fang LI; Yong JIANG; Mei Zhen ZENG; En Yong DING

    2003-01-01

    Natural cellulose with the crystal form of cellulose Ⅰ, when treated with condensed lye(e.g. 18%NaOH), can change into new crystal form of cellulose Ⅱ. But the nano-crystallinecellulose(NCC) can do it when only treated with dilute lye (e.g. 1%NaOH) at room temperatureand even can dissolve into slightly concentrated lye (e.g. 4%NaOH).

  5. Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives

    OpenAIRE

    1982-01-01

    In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presen...

  6. Alexa Fluor-labeled Fluorescent Cellulose Nanocrystals for Bioimaging Solid Cellulose in Spatially Structured Microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G.; Kelly, Ryan T.; Orr, Galya; Hu, Dehong; Dehoff, Karl J.; Brockman, Fred J.; Wilkins, Michael J.

    2015-03-18

    Cellulose nanocrystal materials have been labeled with modern Alexa Fluor dyes in a process that first links the dye to a cyanuric chloride molecule. Subsequent reaction with cellulose nanocrystals provides dyed solid microcrystalline cellulose material that can be used for bioimaging and suitable for deposition in films and spatially structured microenvironments. It is demonstrated with single molecular fluorescence microscopy that these films are subject to hydrolysis by cellulose enzymes.

  7. Nano-cellulose derived bioplastic biomaterial data for vehicle bio-bumper from banana peel waste biomass

    OpenAIRE

    Sharif Hossain, A.B.M.; Ibrahim, Nasir A.; Mohammed Saad AlEissa

    2016-01-01

    The innovative study was carried out to produce nano-cellulose based bioplastic biomaterials for vehicle use coming after bioprocess technology. The data show that nano-cellulose particle size was 20 nm and negligible water absorption was 0.03% in the bioplastic. Moreover, burning test, size and shape characterizations, spray coating dye, energy test and firmness of bioplastic have been explored and compared with the standardization of synthetic vehicle plastic bumper following the American S...

  8. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference.

  9. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE Jun; XIONG Jian; SU Yingzhi; XIAO Ping

    2001-01-01

    @@ Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.

  10. Chemo-catalytic valorization of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Palkovits, R. [RWTH Aachen Univ. (Germany). Inst. fuer Technische und Makromolekulare Chemie

    2012-07-01

    Cellulose can be utilized as carbon source for the production of novel platform molecules as well as fuel motifs. Promising transformation strategies cover the hydrolytic hydrogenation or hydrogenolysis of cellulose to sugar alcohols, the hydrolysis of cellulose to glucose followed by dehydration to 5-hydroxymethylfurfural or levulinic acid and the further hydrogenation of levulinic acid to {gamma}-valerolactone. Main challenges result from the high degree of functionalization of cellulosic feedstocks. In line, processes are carried out in liquid phase utilizing rather polar solvents and aiming for a tailored defunctionalisation of these oxygen rich compounds. Consequently, such transformations require novel strategies concerning the development of suitable catalysts and appropriate process concepts. (orig.)

  11. [Supramolecular reorganizations in cellulose during hydration].

    Science.gov (United States)

    Grunin, Iu B; Grunin, L Iu; Talantsev, V I; Nikol'skaia, E A; Masas, D S

    2015-01-01

    The analysis of modern ideas about the structural organization of the cellulose microfibrils is carried out. The mechanism of the formation of additional capillary-porous system of cellulose under moistening is offered. It is established that when the moisture content of cellulose reaches 8-10%, the filling of its micropores occurs with a simultaneous increase in their cross sizes, a specific surface and reduction in the degree of crystallinity of specimens. Within the proposed model of microfibril construction the parameters of supramolecular structure and capillary-porous system of cotton cellulose are determined.

  12. Simultaneous cellulose conversion and hydrogen production assisted by cellulose decomposition under UV-light photocatalysis.

    Science.gov (United States)

    Zhang, Guan; Ni, Chengsheng; Huang, Xiubing; Welgamage, Aakash; Lawton, Linda A; Robertson, Peter K J; Irvine, John T S

    2016-01-28

    Photocatalytic conversion of cellulose to sugars and carbon dioxide with simultaneous production of hydrogen assisted by cellulose decomposition under UV or solar light irradiation was achieved upon immobilization of cellulose onto a TiO2 photocatalyst. This approach enables production of hydrogen from water without using valuable sacrificial agents, and provides the possibility for recovering sugars as liquid fuels.

  13. Liquid crystalline solutions of cellulose in phosphoric acid for preparing cellulose yarns

    NARCIS (Netherlands)

    Boerstoel, H.

    2006-01-01

    The presen thesis describes a new process for manufacturing high tenacity and high modulus cellulose yarns. A new direct solvent for cellulose has been discovered, leading to liquid crystalline solutions. This new solvent, superphosphoric acid, rapidly dissolves cellulose. These liquid crystalline s

  14. High Performance Regenerated Cellulose Membranes from Trimethylsilyl Cellulose

    KAUST Repository

    Ali, Ola

    2013-05-01

    Regenerated cellulose (RC) membranes are extensively used in medical and pharmaceutical separation processes due to their biocompatibility, low fouling tendency and solvent resistant properties. They typically possess ultrafiltration and microfiltration separation characteristics, but recently, there have been attempts to widen their pool of applications in nanofiltration processes. In this work, a novel method for preparing high performance composite RC membranes was developed. These membranes reveal molecular weight cut-offs (MWCO) of less than 250 daltons, which possibly put them ahead of all commercial RC membranes and in competition with high performance nanofiltration membranes. The membranes were prepared by acidic hydrolysis of dip-coated trimethylsilyl cellulose (TMSC) films. TMSC, with a degree of silylation (DS) of 2.8, was prepared from microcrystalline cellulose by reaction with hexamethyldisilazane under the homogeneous conditions of LiCl/DMAC solvent system. Effects of parameters, such as coating solution concentration and drying rates, were investigated. It was concluded that higher TMSC concentrations as well as higher solvent evaporation rates favor better MWCOs, mainly due to increase in the selective layer thickness. Successful cross-linking of prepared membranes with glyoxal solutions, in the presence of boric acid as a catalyst, resulted in MWCOs less than 250 daltons. The suitability of this crosslinking reaction for large scale productions was already proven in the manufacturing of durable-press fabrics. For us, the inexpensive raw materials as well as the low reaction times and temperatures were of interest. Moreover, the non-toxic nature of glyoxal is a key advantage in medical and pharmaceutical applications. The membranes prepared in this work are strong candidates for separation of small organic solutes from organic solvents streams in pharmaceutical industries. Their hydrophilicity, compared to typical nanofiltration membranes, offer

  15. Clinical Signs of Hairballs in Cats Fed a Diet Enriched with Cellulose

    Directory of Open Access Journals (Sweden)

    A. C. Beynen

    2011-01-01

    Full Text Available Problem statement: The intake of cellulose may delay gastric emptying and raise the intestinal transit rate. These effects could antagonize hairball formation. Thus, it was hypothesized that a diet enriched with a cellulose preparation (Arbocel BWW40®, forming a completely insoluble fiber network, would diminish the severity of clinical symptoms of hairballs in cats. Approach: In a double-blind, placebo-controlled trial with parallel design, 24 privately owned cats were used and the clinical signs were evaluated by the owners. For a period of four weeks, the cats (n = 12 per treatment group consumed a complete dry food without or with 4% (w/w cellulose. During the test period, the control or test diet was the only source of nutrition. The trial questionnaire was in the form of a booklet in which each day the occurrence of hairball symptoms (vomiting, retching and coughing were recorded by the owners. Results: When compared with the control diet, the feeding of the diet with added cellulose lowered the total incidence of vomiting, retching and coughing by 79, 91 and 70%, respectively. The cellulose-induced decrease in vomiting was statistically significant. It is suggested that cellulose ingestion had caused delayed gastric emptying, leading to binding of single strands of hair to food particles so that more hair is transferred into the duodenum. The cellulose-mediated increase in transit rate of digesta may subsequently promote the excretion of hairs with the feces. Conclusion: This study shows that a diet fortified with cellulose reduced the severity of clinical signs in cats with existing hairballs, but the diet may also be effective in the prevention of hairball development.

  16. Nano-tubular cellulose for bioprocess technology development.

    Directory of Open Access Journals (Sweden)

    Athanasios A Koutinas

    Full Text Available Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC justifies its suitability for use in "cold pasteurization" processes and its promoting activity in bioprocessing (fermentation. The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions during freeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator. Moreover, NC may lead to new perspectives in research such as the development of new composites, templates for cylindrical nano-particles, etc.

  17. Regenerated cellulose fibers spun-dyed with carbon black/latex composite dispersion.

    Science.gov (United States)

    Wang, Chunxia; Du, Changsen; Tian, Anli; Fu, Shaohai; Xu, Changhai

    2014-01-30

    A carbon black (CB)/latex composite was prepared by the method of miniemulsion polymerization for use as a colorant for spun dyeing of regenerated cellulose fibers. Analysis of experimental results revealed that the CB/latex composite had a small particle size and a narrow particle size distribution which were important to ensure a stable dispersion being later added to spinning solution. A good stability of the prepared CB/latex composite dispersion in the spinning solution indicated that it was highly possible to use the CB/latex composite as a colorant for spun dyeing of regenerated cellulose fibers. When a 3.5% mass ratio of CB/latex composite to cellulose was used for spun dyeing, the spun-dyed fibers had the highest tensile strength, breaking elongation and color strength. The rubbing and washing color fastnesses of spun-dyed regenerated cellulose fibers could satisfy requirements of most textiles. This study provided a new insight into producing spun-dyed regenerated cellulose with a novel colorant.

  18. Pyrolytic sugars from cellulosic biomass

    Science.gov (United States)

    Kuzhiyil, Najeeb

    Sugars are the feedstocks for many promising advanced cellulosic biofuels. Traditional sugars derived from starch and sugar crops are limited in their availability. In principle, more plentiful supply of sugars can be obtained from depolymerization of cellulose, the most abundant form of biomass in the world. Breaking the glycosidic bonds between the pyranose rings in the cellulose chain to liberate glucose has usually been pursued by enzymatic hydrolysis although a purely thermal depolymerization route to sugars is also possible. Fast pyrolysis of pure cellulose yields primarily levoglucosan, an anhydrosugar that can be hydrolyzed to glucose. However, naturally occurring alkali and alkaline earth metals (AAEM) in biomass are strongly catalytic toward ring-breaking reactions that favor formation of light oxygenates over anhydrosugars. Removing the AAEM by washing was shown to be effective in increasing the yield of anhydrosugars; but this process involves removal of large amount of water from biomass that renders it energy intensive and thereby impractical. In this work passivation of the AAEM (making them less active or inactive) using mineral acid infusion was explored that will increase the yield of anhydrosugars from fast pyrolysis of biomass. Mineral acid infusion was tried by previous researchers, but the possibility of chemical reactions between infused acid and AAEM in the biomass appears to have been overlooked, possibly because metal cations might be expected to already be substantially complexed to chlorine or other strong anions that are found in biomass. Likewise, it appears that previous researchers assumed that as long as AAEM cations were in the biomass, they would be catalytically active regardless of the nature of their complexion with anions. On the contrary, we hypothesized that AAEM can be converted to inactive or less active salts using mineral acids. Various biomass feedstocks were infused with mineral (hydrochloric, nitric, sulfuric and

  19. Comparison of physical properties of regenerated cellulose films fabricated with different cellulose feedstocks in ionic liquid.

    Science.gov (United States)

    Pang, JinHui; Wu, Miao; Zhang, QiaoHui; Tan, Xin; Xu, Feng; Zhang, XueMing; Sun, RunCang

    2015-05-05

    With the serious "white pollution" resulted from the non-biodegradable plastic films, considerable attention has been directed toward the development of renewable and biodegradable cellulose-based film materials as substitutes of petroleum-derived materials. In this study, environmentally friendly cellulose films were successfully prepared using different celluloses (pine, cotton, bamboo, MCC) as raw materials and ionic liquid 1-ethyl-3-methylimidazolium acetate as a solvent. The SEM and AFM indicated that all cellulose films displayed a homogeneous and smooth surface. In addition, the FT-IR and XRD analysis showed the transition from cellulose I to II was occurred after the dissolution and regeneration process. Furthermore, the cellulose films prepared by cotton linters and pine possessed the most excellent thermal stability and mechanical properties, which were suggested by the highest onset temperature (285°C) and tensile stress (120 MPa), respectively. Their excellent properties of regenerated cellulose films are promising for applications in food packaging and medical materials.

  20. Nucleic acids encoding a cellulose binding domain

    Energy Technology Data Exchange (ETDEWEB)

    Shoseyov, Oded (Karmey Yosef, IL); Shpiegl, Itai (Rehovot, IL); Goldstein, Marc A. (Davis, CA); Doi, Roy H. (Davis, CA)

    1996-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  1. Cellulose nanocrystals: synthesis, functional properties, and applications

    Directory of Open Access Journals (Sweden)

    George J

    2015-11-01

    Full Text Available Johnsy George, SN Sabapathi Food Engineering and Packaging Division, Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka, India Abstract: Cellulose nanocrystals are unique nanomaterials derived from the most abundant and almost inexhaustible natural polymer, cellulose. These nanomaterials have received significant interest due to their mechanical, optical, chemical, and rheological properties. Cellulose nanocrystals primarily obtained from naturally occurring cellulose fibers are biodegradable and renewable in nature and hence they serve as a sustainable and environmentally friendly material for most applications. These nanocrystals are basically hydrophilic in nature; however, they can be surface functionalized to meet various challenging requirements, such as the development of high-performance nanocomposites, using hydrophobic polymer matrices. Considering the ever-increasing interdisciplinary research being carried out on cellulose nanocrystals, this review aims to collate the knowledge available about the sources, chemical structure, and physical and chemical isolation procedures, as well as describes the mechanical, optical, and rheological properties, of cellulose nanocrystals. Innovative applications in diverse fields such as biomedical engineering, material sciences, electronics, catalysis, etc, wherein these cellulose nanocrystals can be used, are highlighted. Keywords: sources of cellulose, mechanical properties, liquid crystalline nature, surface modification, nanocomposites 

  2. Idealized powder diffraction patterns for cellulose polymorphs

    Science.gov (United States)

    Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been determined with synchrotron X-radiation and neutron diffrac...

  3. 21 CFR 172.870 - Hydroxypropyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxypropyl cellulose. 172.870 Section 172.870... CONSUMPTION Multipurpose Additives § 172.870 Hydroxypropyl cellulose. The food additive hydroxypropyl... anhydrous basis, not more than 4.6 hydroxypropyl groups per anhydroglucose unit. The additive has a...

  4. Conformational studies of cellulosic fragments by DFT

    Science.gov (United States)

    The study of cellulosic fragments by DFTr is a continuation of our efforts to produce quality structural data that will be valuable to those working in the field of cellulose structure and enzymatic degradation. Using a reduced basis set and density functional DFTr (B3LYP), optimization of cellulosi...

  5. Diffraction from nonperiodic models of cellulose crystals

    Science.gov (United States)

    Powder and fiber diffraction patterns were calculated for model cellulose crystallites with chains 20 glucose units long. Model sizes ranged from four chains to 169 chains, based on cellulose I' coordinates, and were subjected to various combinations of energy minimization and molecular dynamics (M...

  6. BIODEGRADATION OF REGENERATED CELLULOSE FILMS BY FUNGI

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; LIU Haiqing; ZHENG Lianshuang; ZHANG Jiayao; DU Yumin; LIU Weili

    1996-01-01

    The biodegradability of Aspergillus niger (A. niger), Mucor (M-305) and Trichoderma (T-311) strains on regenerated cellulose films in media was investigated. The results showed that T-311 strain isolated from soil adhered on the cellulose film fragments has stronger degradation effect on the cellulose film than A. niger strain. The weights, molecular weights and tensile strengths of the cellulose films in both shake culture and solid media decreased with incubation time, accompanied by producing CO2 and saccharides. HPLC, IR and released CO2 analysis indicated that the biodegradation products of the regenerated cellulose films mainly contain oligosaccharides, cellobiose, glucose, arabinose, erythrose, glycerose,glycerol, ethanal, formaldehyde and organic acid, the end products were CO2 and water.After a month, the films were completely decomposed by fungi in the media at 30℃.

  7. Cellulose Nanocrystals Obtained from Rice By-Products and Their Binding Potential to Metallic Ions

    Directory of Open Access Journals (Sweden)

    Vanessa L. Albernaz

    2015-01-01

    Full Text Available The present study aimed to develop and optimize a method to obtain cellulose nanocrystals from the agricultural by-products rice husk and straw and to evaluate their electrostructural modifications in the presence of metallic ions. First, different particle formation conditions and routes were tested and analyzed by spectrophotometry, dynamic light scattering (DLS, and Zeta potential measurements. Then, electrostructural effects of ions Na(I, Cd(II, and Al(III on the optimized nanoparticles were analyzed by atomic force microscopy (AFM, scanning electron microscopy (SEM, and electrical conductivity (EC assessments. The produced cellulose nanocrystals adopted a rod-like shape. AFM height distribution and EC data indicated that the nanocrystals have more affinity in binding with Na(I > Al(III > Cd(II. These data suggest that the use of these cellulose nanocrystals in the bioremediation field is promising, both in metal sorption from wastewater and as an alternative for water desalination.

  8. Synthesis, antibacterial and thermal studies of cellulose nanocrystal stabilized ZnO-Ag heterostructure nanoparticles.

    Science.gov (United States)

    Azizi, Susan; Ahmad, Mansor Bin Hj; Hussein, Mohd Zobir; Ibrahim, Nor Azowa

    2013-05-28

    Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs) as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO₃ relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9-35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals.

  9. SYNTHESIS AND CHARACTERIZATION OF CELLULOSE-GRAFT-POLY (L-LACTIDE VIA RING-OPENING POLYMERIZATION

    Directory of Open Access Journals (Sweden)

    Shu Xiao,

    2012-02-01

    Full Text Available Cellulose-graft-poly (L-lactide (cellulose-g-PLLA was prepared under homogeneous mild conditions. Ring-opening polymerization (ROP was carried out successfully using 4-dimethylaminopyridine (DMAP as an organic catalyst in an ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl. The structure of the polymer was characterized by GPC, 1H NMR, 13C NMR, FT-IR, TGA, WAXD, and AFM. The results indicated that the grafting rate of the polymer reached 4.44, which was higher than that reported in AmimCl with Sn(oct2 as a catalyst. In addition, AFM showed that the polymer in solution could aggregate and self-assemble into an approximately spherical structure, which was different from the rod-like structure of cellulose and round-like polylactic acid particles.

  10. Enhancement of Cellulose Degradation by Cattle Saliva.

    Science.gov (United States)

    Seki, Yasutaka; Kikuchi, Yukiko; Kimura, Yoshihiro; Yoshimoto, Ryo; Takahashi, Masatoshi; Aburai, Kenichi; Kanai, Yoshihiro; Ruike, Tatsushi; Iwabata, Kazuki; Sugawara, Fumio; Sakai, Hideki; Abe, Masahiko; Sakaguchi, Kengo

    2015-01-01

    Saccharification of cellulose is a promising technique for producing alternative source of energy. However, the efficiency of conversion of cellulose into soluble sugar using any currently available methodology is too low for industrial application. Many additives, such as surfactants, have been shown to enhance the efficiency of cellulose-to-sugar conversion. In this study, we have examined first whether cattle saliva, as an additive, would enhance the cellulase-catalyzed hydrolysis of cellulose, and subsequently elucidated the mechanism by which cattle saliva enhanced this conversion. Although cattle saliva, by itself, did not degrade cellulose, it enhanced the cellulase-catalyzed degradation of cellulose. Thus, the amount of reducing sugar produced increased approximately 2.9-fold by the addition of cattle saliva. We also found that non-enzymatic proteins, which were present in cattle saliva, were responsible for causing the enhancement effect. Third, the mechanism of cattle saliva mediated enhancement of cellulase activity was probably similar to that of the canonical surfactants. Cattle saliva is available in large amounts easily and cheaply, and it can be used without further purification. Thus, cattle saliva could be a promising additive for efficient saccharification of cellulose on an industrial scale.

  11. Utilization of purified cellulose in fiber studies.

    Science.gov (United States)

    Penner, M H; Liaw, E T

    1990-01-01

    Purified cellulose-type fiber products are widely used in experimental nutrition. Their use in a broad spectrum of studies may potentially lead to the acceptance of the misconception that the various commercially available cellulose products are equivalent. In this paper we have attempted to show that this is not the case. The comparative structural data of Table 2 and the compositional data of Olsen et al provide examples which indicate that purified cellulose preparations should not necessarily be considered equivalent. Unfortunately, our current lack of understanding of how fibers are metabolized and how they may affect specific physiological parameters makes it difficult to determine which, if any, of the measurable structural and chemical properties will be of relevance for a given in vivo study. At present, it appears that researchers utilizing/evaluating the consequences of consuming a purified cellulose-type fiber would be prudent to provide at least a limited amount of data on the properties of the cellulose preparation used in their studies. The characterization of the cellulose product may be done by a variety of methods depending on the expertise of the laboratory. The methods and results discussed in this paper provide an example of the type of information which may be obtained from an in vitro characterization of cellulose products.

  12. Effect of Mild Acid Hydrolysis Parameters on Properties of Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Kari Mikael Vanhatalo

    2014-06-01

    Full Text Available The effects of mild kraft pulp hydrolysis conditions (reaction time, temperature, pulp consistency, and acid dosage with sulfuric acid (H2SO4 on the properties of microcrystalline cellulose (MCC were investigated. The degree of polymerization (DP of cellulose rapidly decreased at the initiation of hydrolysis and leveled off after a certain reaction time, depending on the hydrolysis conditions. The intensity of the hydrolysis treatment greatly affected the cellulose particle size. Compared to the intensive treatment, the mild conditions resulted in a broader particle size distribution, while smaller particles with a narrow size distribution were obtained under severe conditions. However, the particle size leveled off at a hydrolysis factor (P-factor of 300. The results suggest that after a certain P-factor (300, severe hydrolysis conditions have no advantage over mild ones as related to the MCC particle properties. Because of favourable reaction conditions (short delay time, moderate temperature, and small amounts of chemicals, this method can be implemented on an industrial scale in a chemical pulp mill.

  13. A novel cellulose hydrogel prepared from its ionic liquid solution

    Institute of Scientific and Technical Information of China (English)

    LI Lu; LIN ZhangBi; YANG Xiao; WAN ZhenZhen; CUI ShuXun

    2009-01-01

    A novel cellulose hydrogel is prepared by regenerating cellulose from its ionic liquid solution. The transparency cellulose hydrogel presents a good chemical stability and an acceptable mechanical property. This non-toxic cellulose hydrogel should be biocompatibie and may be useful in the future as a biomaterial.

  14. Model films of cellulose. I. Method development and initial results

    NARCIS (Netherlands)

    Gunnars, S.; Wågberg, L.; Cohen Stuart, M.A.

    2002-01-01

    This report presents a new method for the preparation of thin cellulose films. NMMO (N- methylmorpholine- N-oxide) was used to dissolve cellulose and addition of DMSO (dimethyl sulfoxide) was used to control viscosity of the cellulose solution. A thin layer of the cellulose solution is spin- coated

  15. Lyocell, The New Generation of Regenerated Cellulose

    Directory of Open Access Journals (Sweden)

    Éva Borbély

    2008-06-01

    Full Text Available For the majority of the last century, commercial routes to regenerated cellulosefibres have coped with the difficulties of making a good cellulose solution by using an easyto dissolve derivative (e.g. xanthane in the case of viscose rayon or complex (e.g.cuprammonium rayon. For the purposes of this paper, advanced cellulosic fibres aredefined as those made from a process involving direct dissolution of cellulose. The firstexamples of such fibres have now been generically designaed as lyocell fibres todistinguish them from rayons, and the first commercial lyocell fibre is Courtaulds’ Tencel.

  16. Visualising recalcitrance by colocalisation of cellulase, lignin and cellulose in pretreated pine biomass using fluorescence microscopy

    Science.gov (United States)

    Donaldson, Lloyd; Vaidya, Alankar

    2017-01-01

    Mapping the location of bound cellulase enzymes provides information on the micro-scale distribution of amenable and recalcitrant sites in pretreated woody biomass for biofuel applications. The interaction of a fluorescently labelled cellulase enzyme cocktail with steam-exploded pine (SEW) was quantified using confocal microscopy. The spatial distribution of Dylight labelled cellulase was quantified relative to lignin (autofluorescence) and cellulose (Congo red staining) by measuring their colocalisation using Pearson correlations. Correlations were greater in cellulose-rich secondary cell walls compared to lignin-rich middle lamella but with significant variations among individual biomass particles. The distribution of cellulose in the pretreated biomass accounted for 30% of the variation in the distribution of enzyme after correcting for the correlation between lignin and cellulose. For the first time, colocalisation analysis was able to quantify the spatial distribution of amenable and recalcitrant sites in relation to the histochemistry of cellulose and lignin. This study will contribute to understanding the role of pretreatment in enzymatic hydrolysis of recalcitrant softwood biomass. PMID:28281670

  17. Visualising recalcitrance by colocalisation of cellulase, lignin and cellulose in pretreated pine biomass using fluorescence microscopy

    Science.gov (United States)

    Donaldson, Lloyd; Vaidya, Alankar

    2017-03-01

    Mapping the location of bound cellulase enzymes provides information on the micro-scale distribution of amenable and recalcitrant sites in pretreated woody biomass for biofuel applications. The interaction of a fluorescently labelled cellulase enzyme cocktail with steam-exploded pine (SEW) was quantified using confocal microscopy. The spatial distribution of Dylight labelled cellulase was quantified relative to lignin (autofluorescence) and cellulose (Congo red staining) by measuring their colocalisation using Pearson correlations. Correlations were greater in cellulose-rich secondary cell walls compared to lignin-rich middle lamella but with significant variations among individual biomass particles. The distribution of cellulose in the pretreated biomass accounted for 30% of the variation in the distribution of enzyme after correcting for the correlation between lignin and cellulose. For the first time, colocalisation analysis was able to quantify the spatial distribution of amenable and recalcitrant sites in relation to the histochemistry of cellulose and lignin. This study will contribute to understanding the role of pretreatment in enzymatic hydrolysis of recalcitrant softwood biomass.

  18. Comment on Shvedova et al. (2016), "gender differences in murine pulmonary responses elicited by cellulose nanocrystals".

    Science.gov (United States)

    Shatkin, Jo Anne; Oberdörster, Günter

    2016-11-04

    A recent publication in "Particle and Fibre Toxicology" reported on the gender differences in pulmonary toxicity from oro-pharyngeal aspiration of a high dose of cellulose nanocrystals. The study is timely given the growing interest in diverse commercial applications of cellulose nanomaterials, and the need for studies addressing pulmonary toxicity. The results from this study are interesting and can be strengthened with a discussion of how differences in the weights of female and male C57BL/6 mice was accounted for. Without such a discussion, the observed differences could be partially explained by the lower body weights of females, resulting in higher doses than males when standardized to body weight or lung volume. Further, few conclusions can be drawn about the pulmonary toxicity of cellulose nanocrystals given the study design: examination of a single high dose of cellulose nanocrystals, administered as a bolus, without positive or negative controls or low dose comparisons, and at an unphysiological and high dose rate. Simulating the bolus type delivery by inhalation would require a highly unrealistic exposure concentration in the g/m(3) range of extremely short duration. A discussion of these limitations is missing in the paper; further speculative comparisons of cellulose nanocrystals toxicity to asbestos and carbon nanotubes in the abstract are both unwarranted and can be misleading, these materials were neither mentioned in the manuscript, nor evaluated in the study.

  19. Optimized Monitoring of Production of Cellulose Nanowhiskers from Opuntia ficus-indica (Nopal Cactus

    Directory of Open Access Journals (Sweden)

    Horacio Vieyra

    2015-01-01

    Full Text Available Preparation of cellulose nanowhiskers (CNWs has grown significantly because they are useful for a wide range of applications. Additional advantage in their design requires that they meet the following characteristics: nontoxicity, abundance, sustainability, renewability, and low cost. To address these requirements, nanowhiskers were prepared from Opuntia ficus-indica (nopal cellulose by acid hydrolysis. Monitoring the process of CNWs preparation is necessary to ensure maximum yield and purity of the end product. In this study, the cellulose preparation was monitored by analyzing microscopic morphology by SEM; the purity degree was determined by fluorescence microscopy as a novel and rapid technique, and FTIR spectroscopy was used for confirmation. The additional parameters that monitored the process were the crystallinity index by X-ray diffraction and the size of the particle by dynamic light scattering (DLS. Nopal cellulose was found to be comparable to commercial microcrystalline cellulose. The use of Opuntia ficus-indica is a viable alternative for the production of highly pure CNWs and the strategy to supervise the preparation process was rapid.

  20. Micro-Nanostructured Polyaniline Assembled in Cellulose Matrix via Interfacial Polymerization for Applications in Nerve Regeneration.

    Science.gov (United States)

    Xu, Dingfeng; Fan, Lin; Gao, Lingfeng; Xiong, Yan; Wang, Yanfeng; Ye, Qifa; Yu, Aixi; Dai, Honglian; Yin, Yixia; Cai, Jie; Zhang, Lina

    2016-07-13

    Conducting polymers have emerged as frontrunners to be alternatives for nerve regeneration, showing a possibility of the application of polyaniline (PANI) as the nerve guidance conduit. In the present work, the cellulose hydrogel was used as template to in situ synthesize PANI via the limited interfacial polymerization method, leading to one conductive side in the polymer. PANI sub-micrometer dendritic particles with mean diameter of ∼300 nm consisting of the PANI nanofibers and nanoparticles were uniformly assembled into the cellulose matrix. The hydrophobic PANI nanoparticles were immobilized in the hydrophilic cellulose via the phytic acid as "bridge" at presence of water through hydrogen bonding interaction. The PANI/cellulose composite hydrogels exhibited good mechanical properties and biocompatibility as well as excellent guiding capacity for the sciatic nerve regeneration of adult Sprague-Dawley rats without any extra treatment. On the basis of the fact that the pure cellulose hydrogel was an inert material for the neural repair, PANI played an indispensable role on the peripheral nerve regeneration. The hierarchical micro-nanostructure and electrical conductivity of PANI could remarkably induce the adhesion and guiding extension of neurons, showing its great potential in biomedical materials.

  1. Cellulose-builder: a toolkit for building crystalline structures of cellulose.

    Science.gov (United States)

    Gomes, Thiago C F; Skaf, Munir S

    2012-05-30

    Cellulose-builder is a user-friendly program that builds crystalline structures of cellulose of different sizes and geometries. The program generates Cartesian coordinates for all atoms of the specified structure in the Protein Data Bank format, suitable for using as starting configurations in molecular dynamics simulations and other calculations. Crystalline structures of cellulose polymorphs Iα, Iβ, II, and III(I) of practically any size are readily constructed which includes parallelepipeds, plant cell wall cellulose elementary fibrils of any length, and monolayers. Periodic boundary conditions along the crystallographic directions are easily imposed. The program also generates atom connectivity file in PSF format, required by well-known simulation packages such as NAMD, CHARMM, and others. Cellulose-builder is based on the Bash programming language and should run on practically any Unix-like platform, demands very modest hardware, and is freely available for download from ftp://ftp.iqm.unicamp.br/pub/cellulose-builder.

  2. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Science.gov (United States)

    Liu, Lifeng; Shang-Guan, Keke; Zhang, Baocai; Liu, Xiangling; Yan, Meixian; Zhang, Lanjun; Shi, Yanyun; Zhang, Mu; Qian, Qian; Li, Jiayang; Zhou, Yihua

    2013-01-01

    Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1), a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI) anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM) at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD) assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs) function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  3. Brittle Culm1, a COBRA-like protein, functions in cellulose assembly through binding cellulose microfibrils.

    Directory of Open Access Journals (Sweden)

    Lifeng Liu

    Full Text Available Cellulose represents the most abundant biopolymer in nature and has great economic importance. Cellulose chains pack laterally into crystalline forms, stacking into a complicated crystallographic structure. However, the mechanism of cellulose crystallization is poorly understood. Here, via functional characterization, we report that Brittle Culm1 (BC1, a COBRA-like protein in rice, modifies cellulose crystallinity. BC1 was demonstrated to be a glycosylphosphatidylinositol (GPI anchored protein and can be released into cell walls by removal of the GPI anchor. BC1 possesses a carbohydrate-binding module (CBM at its N-terminus. In vitro binding assays showed that this CBM interacts specifically with crystalline cellulose, and several aromatic residues in this domain are essential for binding. It was further demonstrated that cell wall-localized BC1 via the CBM and GPI anchor is one functional form of BC1. X-ray diffraction (XRD assays revealed that mutations in BC1 and knockdown of BC1 expression decrease the crystallite width of cellulose; overexpression of BC1 and the CBM-mutated BC1s caused varied crystallinity with results that were consistent with the in vitro binding assay. Moreover, interaction between the CBM and cellulose microfibrils was largely repressed when the cell wall residues were pre-stained with two cellulose dyes. Treating wild-type and bc1 seedlings with the dyes resulted in insensitive root growth responses in bc1 plants. Combined with the evidence that BC1 and three secondary wall cellulose synthases (CESAs function in different steps of cellulose production as revealed by genetic analysis, we conclude that BC1 modulates cellulose assembly by interacting with cellulose and affecting microfibril crystallinity.

  4. BIOSYNTHESIS OF BACTERIAL CELLULOSE BY МEDUSOMYCES GISEVII

    OpenAIRE

    E. K. Gladysheva; E. A. Skiba

    2015-01-01

    Summary: Bacterial cellulose is an organic material that is synthesized by microorganisms extracellularly. Bacterial cellulose can be used in various industries. Especially, bacterial cellulose has found its application basically in medicine. The production of bacterial cellulose is a complicated and long process. The principal criterion for the process to be successful is bacterial cellulose to be obtained in a higher yield. Russia is lacking an operating facility to produce bacterial cellul...

  5. Novel co-processed excipients of mannitol and microcrystalline cellulose for preparing fast dissolving tablets of glipizide

    Directory of Open Access Journals (Sweden)

    Jacob S

    2007-01-01

    Full Text Available Co-processed particles of microcrystalline cellulose and mannitol were fabricated by spray drying technique to be used as a direct compression excipient in fast dissolving tablet formulation. Microcrystalline cellulose passed through sieve no.80, having a volumetric mean diameter (d 50 of 28.35 µm, was used to form composite particles with powdered mannitol which was previously passed through sieve no. 80, in various mixing ratios. The composite particles were evaluated for their powder and compression properties. An increase in the microcrystalline cellulose proportion imparted greater compressibility to the composite particles, but the flowability of these mixtures was decreased. Although microcrystalline cellulose and mannitol have been extensively used in the formulation of fast dissolving tablets, the non-wetting property of the hard compact central core may delay the disintegration time. Optimized co-processed formulation containing mannitol and microcrystalline cellulose in the ratio of 1.25:1 was found to have optimized powder and compressibility characteristics with fast disintegrating property (< 15 s. Photomicrographs have shown that the mannitol crystals are fine and uniformly distributed in the microcrystalline matrix in spray dried form compared to physical mixture of the same combination. The fast disintegration may be due to the partial amorphization and formation of submicron particles of mannitol. These results indicated that improved fast dissolving tablets could be prepared by the co-processed mixture of microcrystalline cellulose and mannitol. Finally fast dissolving tablets of glipizide were prepared by blending with other excipients and compressed into tablets. Sensory study on disintegration time and mouth feel attributes ranked the present formulation based on grittiness, chalkiness and overall preference as the best.

  6. Optimizing Extraction of Cellulose and Synthesizing Pharmaceutical Grade Carboxymethyl Sago Cellulose from Malaysian Sago Pulp

    Directory of Open Access Journals (Sweden)

    Anand Kumar Veeramachineni

    2016-06-01

    Full Text Available Sago biomass is an agro-industrial waste produced in large quantities, mainly in the Asia-Pacific region and in particular South-East Asia. This work focuses on using sago biomass to obtain cellulose as the raw material, through chemical processing using acid hydrolysis, alkaline extraction, chlorination and bleaching, finally converting the material to pharmaceutical grade carboxymethyl sago cellulose (CMSC by carboxymethylation. The cellulose was evaluated using Thermogravimetric Analysis (TGA, Infrared Spectroscopy (FTIR, X-Ray Diffraction (XRD, Differential Scanning Calorimetry (DSC and Field Emission Scanning Electronic Microscopy (FESEM. The extracted cellulose was analyzed for cellulose composition, and subsequently modified to CMSC with a degree of substitution (DS 0.6 by typical carboxymethylation reactions. X-ray diffraction analysis indicated that the crystallinity of the sago cellulose was reduced after carboxymethylation. FTIR and NMR studies indicate that the hydroxyl groups of the cellulose fibers were etherified through carboxymethylation to produce CMSC. Further characterization of the cellulose and CMSC were performed using FESEM and DSC. The purity of CMSC was analyzed according to the American Society for Testing and Materials (ASTM International standards. In this case, acid and alkaline treatments coupled with high-pressure defibrillation were found to be effective in depolymerization and defibrillation of the cellulose fibers. The synthesized CMSC also shows no toxicity in the cell line studies and could be exploited as a pharmaceutical excipient.

  7. Pre-irradiation grafting of cellulose and slightly carboxymethylated cellulose (CMC) fibres

    Energy Technology Data Exchange (ETDEWEB)

    Benke, N. [Institute of Isotopes, HAS, Budapest (Hungary); Takacs, E. [Institute of Isotopes, HAS, Budapest (Hungary)]. E-mail: takacs@iki.kfki.hu; Wojnarovits, L. [Institute of Isotopes, HAS, Budapest (Hungary); Borsa, J. [Budapest University of Technology and Economics, Budapest (Hungary)

    2007-08-15

    Acrylamide, hydroxypropyl acrylate, hydroxypropyl methacrylate and 2-ethylhexyl methacrylate vinyl monomers were grafted onto cellulose as well as onto cellulose of improved accessibility (slightly carboxymethylated cellulose (CMC)) by the pre-irradiation grafting technique. The effect of dose, monomer structure, crosslinking agent and carboxymethylation on the grafting yield was studied and the optimal conditions for the grafting were established. Grafting, with the exception of acrylamide (AAm), decreased the swelling of the samples, which is advantageous for some applications. In case of AAm decrease in swelling was observed only when crosslinking agent was applied. At low doses (<5 kGy) the high accessibility of carboxymethylated cellulose resulted in a higher grafting yield.

  8. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiapeng, E-mail: firgexiao@sina.cn; Pang, Zengyuan, E-mail: pangzengyuan1212@163.com; Yang, Jie, E-mail: young1993@126.com; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn; Cai, Yibing, E-mail: yibingcai@jiangnan.edu.cn; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors.

  9. Efficient cellulose solvent: quaternary ammonium chlorides.

    Science.gov (United States)

    Kostag, Marc; Liebert, Tim; El Seoud, Omar A; Heinze, Thomas

    2013-10-01

    Pure quaternary tetraalkylammonium chlorides with one long alkyl chain dissolved in various organic solvents constitute a new class of cellulose solvents. The electrolytes are prepared in high yields and purity by Menshutkin quaternization, an inexpensive and easy synthesis route. The pure molten tetraalkylammonium chlorides dissolve up to 15 wt% of cellulose. Cosolvents, including N,N-dimethylacetamide (DMA), may be added in large excess, leading to a system of decreased viscosity. Contrary to the well-established solvent DMA/LiCl, cellulose dissolves in DMA/quaternary ammonium chlorides without any pretreatment. Thus, the use of the new solvent avoids some disadvantages of DMA/LiCl and ionic liquids, the most extensively employed solvents for homogeneous cellulose chemistry.

  10. Rapid saccharification for production of cellulosic biofuels.

    Science.gov (United States)

    Lee, Dae-Seok; Wi, Seung Gon; Lee, Soo Jung; Lee, Yoon-Gyo; Kim, Yeong-Suk; Bae, Hyeun-Jong

    2014-04-01

    The economical production of biofuels is hindered by the recalcitrance of lignocellulose to processing, causing high consumption of processing enzymes and impeding hydrolysis of pretreated lignocellulosic biomass. We determined the major rate-limiting factor in the hydrolysis of popping pre-treated rice straw (PPRS) by examining cellulase adsorption to lignin and cellulose, amorphogenesis of PPRS, and re-hydrolysis. Based on the results, equivalence between enzyme loading and the open structural area of cellulose was required to significantly increase productive adsorption of cellulase and to accelerate enzymatic saccharification of PPRS. Amorphogenesis of PPRS by phosphoric acid treatment to expand open structural area of the cellulose fibers resulted in twofold higher cellulase adsorption and increased the yield of the first re-hydrolysis step from 13% to 46%. The total yield from PPRS was increased to 84% after 3h. These results provide evidence that cellulose structure is one of major effects on the enzymatic hydrolysis.

  11. Carboxymethylation of Cellulose by Microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    YE; Jun

    2001-01-01

    Cellulose may be readily converted into ethers involving primary and secondary alcohol groups in each monomer unit and the glycosidic bonds. However, these reactions are rather more complicated than with simple substances, because the stereochemistry of the cellulose molecule is such that the vast majority of its hydroxyl groups form intra-chain hydrogen bonds or inter-chain hydrogen bonds with contiguous molecules. Carboxymethylcellulose (CMC) has played an important part in the commercial uses of cellulose derivatives. CMC becomes alkali and water soluble. The polarity can, in fact, be increased by introduction of ionizing groups, ie carboxymethyl group. CMC is generally produced by the reaction of alkali cellulose with chloroacetic acid.……

  12. Dissolution enthalpies of cellulose in ionic liquids.

    Science.gov (United States)

    Parviainen, Helena; Parviainen, Arno; Virtanen, Tommi; Kilpeläinen, Ilkka; Ahvenainen, Patrik; Serimaa, Ritva; Grönqvist, Stina; Maloney, Thaddeus; Maunu, Sirkka Liisa

    2014-11-26

    In this work, interactions between cellulose and ionic liquids were studied calorimetrically and by optical microscopy. Two novel ionic liquids (1,5-Diazabicyclo[4.3.0]non-5-enium propionate and N-methyl-1,5-diazabicyclo[4.3.0]non-5-enium dimethyl phosphate) and 1-ethyl-3-methylimidazolium acetate-water mixtures were used as solvents. Optical microscopy served in finding the extent of dissolution and identifying the dissolution pattern of the cellulose sample. Calorimetric studies identified a peak relating to dissolution of cellulose in solvent. The transition did, however, not indicate complete dissolution, but rather dissolution inside fibre or fibrils. This method was used to study differences between four cellulose samples with different pretreatment or origins.

  13. The Effect of Mechanochemical Treatment of the Cellulose on Characteristics of Nanocellulose Films

    Science.gov (United States)

    Barbash, V. A.; Yaschenko, O. V.; Alushkin, S. V.; Kondratyuk, A. S.; Posudievsky, O. Y.; Koshechko, V. G.

    2016-09-01

    The development of the nanomaterials with the advanced functional characteristics is a challenging task because of the growing demand in the market of the optoelectronic devices, biodegradable plastics, and materials for energy saving and energy storage. Nanocellulose is comprised of the nanosized cellulose particles, properties of which depend on characteristics of plant raw materials as well as methods of nanocellulose preparation. In this study, the effect of the mechanochemical treatment of bleached softwood sulfate pulp on the optical and mechanical properties of nanocellulose films was assessed. It was established that the method of the subsequent grinding, acid hydrolysis and ultrasound treatment of cellulose generated films with the significant transparency in the visible spectral range (up to 78 % at 600 nm), high Young's modulus (up to 8.8 GPa), and tensile strength (up to 88 MPa) with increased ordering of the packing of the cellulose macromolecules. Morphological characterization was done using the dynamic light scattering (DLS) analyzer and transmission electron microscopy (TEM). The nanocellulose particles had an average diameter of 15-30 nm and a high aspect ratio in the range 120-150. The crystallinity was increased with successive treatments as shown by the X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis. The thermal degradation behavior of cellulose samples was explored by thermal gravimetric analysis (TGA).

  14. Co-processing as a tool to improve aqueous dispersibility of cellulose ethers.

    Science.gov (United States)

    Sharma, Payal; Modi, Sameer R; Bansal, Arvind K

    2015-01-01

    Cellulose ethers are important materials with numerous applications in pharmaceutical industry. They are widely employed as stabilizers and viscosity enhancers for dispersed systems, binders in granulation process and as film formers for tablets. These polymers, however, exhibit challenge during preparation of their aqueous dispersions. Rapid hydration of their surfaces causes formation of a gel that prevents water from reaching the inner core of the particle. Moreover, the surfaces of these particles become sticky, thus leading to agglomeration, eventually reducing their dispersion kinetics. Numerous procedures have been tested to improve dispersibility of cellulose ethers. These include the use of cross-linking agents, alteration in the synthesis process, adjustment of water content of cellulose ether, modification by attaching hydrophobic substituents and co-processing using various excipients. Among these, co-processing has provided the most encouraging results. This review focuses on the molecular mechanisms responsible for the poor dispersibility of cellulose ethers and the role of co-processing technologies in overcoming the challenge. An attempt has been made to highlight various co-processing techniques and specific role of excipients used for co-processing.

  15. Cellulose based cationic adsorbent fabricated via radiation grafting process for treatment of dyes waste water.

    Science.gov (United States)

    Goel, Narender Kumar; Kumar, Virendra; Misra, Nilanjal; Varshney, Lalit

    2015-11-05

    A cationized adsorbent was prepared from cellulosic cotton fabric waste via a single step-green-radiation grafting process using gamma radiation source, wherein poly[2-(methacryloyloxy) ethyl]trimethylammonium chloride (PMAETC) was covalently attached to cotton cellulose substrate. Radiation grafted (PMAETC-g-cellulose) adsorbent was investigated for removal of acid dyes from aqueous solutions using two model dyes: Acid Blue 25 (AB25) and Acid Blue 74 (AB74). The equilibrium adsorption data was analyzed by Langmuir and Freundlich isotherms, whereas kinetic data was analyzed by pseudo first order, pseudo second order, intra particle diffusion and Boyd's models. The PMAETC-g-cellulose adsorbent with 25% grafting yield exhibited equilibrium adsorption capacities of ∼ 540.0mg/g and ∼ 340.0mg/g for AB25 and AB74, respectively. Linear and nonlinear fitting of adsorption data suggested that the equilibrium adsorption process followed Langmuir adsorption isotherm model, whereas, the kinetic adsorption process followed pseudo-second order model. The multi-linearities observed in the intra-particle kinetic plots suggested that the intraparticle diffusion was not the only rate-controlling process in the adsorption of acid dyes on the adsorbent, which was further supported by Boyd's model. The adsorbent could be regenerated by eluting the adsorbed dye from the adsorbent and could be repeatedly used.

  16. Biopolymer foams - Relationship between material characteristics and foaming behavior of cellulose based foams

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, F., E-mail: florian.rapp@ict.fraunhofer.de, E-mail: anja.schneider@ict.fraunhofer.de; Schneider, A., E-mail: florian.rapp@ict.fraunhofer.de, E-mail: anja.schneider@ict.fraunhofer.de [Fraunhofer Institute for Chemical Technology ICT (Germany); Elsner, P., E-mail: peter.elsner@ict.fraunhofer.de [Fraunhofer Institute for Chemical Technology ICT, Germany and Karlsruhe Institute of Technology KIT (Germany)

    2014-05-15

    Biopolymers are becoming increasingly important to both industry and consumers. With regard to waste management, CO{sub 2} balance and the conservation of petrochemical resources, increasing efforts are being made to replace standard plastics with bio-based polymers. Nowadays biopolymers can be built for example of cellulose, lactic acid, starch, lignin or bio mass. The paper will present material properties of selected cellulose based polymers (cellulose propionate [CP], cellulose acetate butyrate [CAB]) and corresponding processing conditions for particle foams as well as characterization of produced parts. Special focus is given to the raw material properties by analyzing thermal behavior (differential scanning calorimetry), melt strength (Rheotens test) and molecular weight distribution (gel-permeation chromatography). These results will be correlated with the foaming behavior in a continuous extrusion process with physical blowing agents and underwater pelletizer. Process set-up regarding particle foam technology, including extrusion foaming and pre-foaming, will be shown. The characteristics of the resulting foam beads will be analyzed regarding part density, cell morphology and geometry. The molded parts will be tested on thermal conductivity as well as compression behavior (E-modulus, compression strength)

  17. Cellulose-water interaction: a spectroscopic study

    OpenAIRE

    Lindh, Erik L

    2016-01-01

    The human society of today has a significantly negative impact on the environment and needs to change its way of living towards a more sustainable path if to continue to live on a healthy planet. One path is believed to be an increased usage of naturally degradable and renewable raw materials and, therefore, attention has been focused on the highly abundant biopolymer cellulose. However, a large drawback with cellulose-based materials is the significant change of their mechanical properties w...

  18. Isolation of cellulose microfibrils - An enzymatic approach

    Directory of Open Access Journals (Sweden)

    Sain, M.

    2006-11-01

    Full Text Available Isolation methods and applications of cellulose microfibrils are expanding rapidly due to environmental benefits and specific strength properties, especially in bio-composite science. In this research, we have success-fully developed and explored a novel bio-pretreatment for wood fibre that can substantially improve the microfibril yield, in comparison to current techniques used to isolate cellulose microfibrils. Microfibrils currently are isolated in the laboratory through a combination of high shear refining and cryocrushing. A high energy requirement of these procedures is hampering momentum in the direction of microfibril isolation on a sufficiently large scale to suit potential applications. Any attempt to loosen up the microfibrils by either complete or partial destruction of the hydrogen bonds before the mechanical process would be a step forward in the quest for economical isolation of cellulose microfibrils. Bleached kraft pulp was treated with OS1, a fungus isolated from Dutch Elm trees infected with Dutch elm disease, under different treatment conditions. The percentage yield of cellulose microfibrils, based on their diameter, showed a significant shift towards a lower diameter range after the high shear refining, compared to the yield of cellulose microfibrils from untreated fibres. The overall yield of cellulose microfibrils from the treated fibres did not show any sizeable decrease.

  19. Utilization of biocatalysts in cellulose waste minimization

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, J.; Evans, B.R.

    1996-09-01

    Cellulose, a polymer of glucose, is the principal component of biomass and, therefore, a major source of waste that is either buried or burned. Examples of biomass waste include agricultural crop residues, forestry products, and municipal wastes. Recycling of this waste is important for energy conservation as well as waste minimization and there is some probability that in the future biomass could become a major energy source and replace fossil fuels that are currently used for fuels and chemicals production. It has been estimated that in the United States, between 100-450 million dry tons of agricultural waste are produced annually, approximately 6 million dry tons of animal waste, and of the 190 million tons of municipal solid waste (MSW) generated annually, approximately two-thirds is cellulosic in nature and over one-third is paper waste. Interestingly, more than 70% of MSW is landfilled or burned, however landfill space is becoming increasingly scarce. On a smaller scale, important cellulosic products such as cellulose acetate also present waste problems; an estimated 43 thousand tons of cellulose ester waste are generated annually in the United States. Biocatalysts could be used in cellulose waste minimization and this chapter describes their characteristics and potential in bioconversion and bioremediation processes.

  20. Biohydrogen, bioelectricity and bioalcohols from cellulosic materials

    Energy Technology Data Exchange (ETDEWEB)

    Nissila, M.

    2013-03-01

    The demand for renewable energy is increasing due to increasing energy demand and global warming associated with increasing use of fossil fuels. Renewable energy can be derived from biological production of energy carriers from cellulosic biomass. These biochemical processes include biomass fermentation to hydrogen, methane and alcohols, and bioelectricity production in microbial fuel cells (MFCs). The objective of this study was to investigate the production of different energy carriers (hydrogen, methane, ethanol, butanol, bioelectricity) through biochemical processes. Hydrogen production potential of a hot spring enrichment culture from different sugars was determined, and hydrogen was produced continuously from xylose. Cellulolytic and hydrogenic cultures were enriched on cellulose, cellulosic pulp materials, and on silage at different process conditions. The enrichment cultures were further characterized. The effect of acid pretreatment on hydrogen production from pulp materials was studied and compared to direct pulp fermentation to hydrogen. Electricity and alcohol(s) were simultaneously produced from xylose in MFCs and the exoelectrogenic and alcohologenic enrichment cultures were characterized. In the end, the energy yields obtained from different biochemical processes were determined and compared. In this study, cultures carrying out simultaneous cellulose hydrolysis and hydrogen fermentation were enriched from different sources at different operational conditions. These cultures were successfully utilized for cellulose to hydrogen fermentation in batch systems. Based on these results further research should be conducted on continuous hydrogen production from cellulosic materials.

  1. Versatile Molding Process for Tough Cellulose Hydrogel Materials.

    Science.gov (United States)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P

    2015-11-05

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes.

  2. Reinforcement of all-cellulose nanocomposite films using native cellulose nanofibrils.

    Science.gov (United States)

    Zhao, Jiangqi; He, Xu; Wang, Yaru; Zhang, Wei; Zhang, Xinxing; Zhang, Xiaodan; Deng, Yulin; Lu, Canhui

    2014-04-15

    All-cellulose nanocomposite films were prepared using native cellulose nanofibrils (CNFs) as fillers and lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) dissolved regenerated cellulose as the matrix. The CNFs, with diameters in the range of 15-40 nm were obtained by combined physical methods of ultrasonic treatment and high shear homogenization. The morphology, structure, and properties of the nanocomposite films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), optical transmittance, thermal gravimetric analysis (TGA), and mechanical testing. The nanocomposite films exhibited good optical transparency, thermal stability, and remarkably enhanced mechanical properties compared to the regenerated cellulose matrix. By varying the CNFs content, the tensile strength of the nanocomposite films increased from 61.56 MPa to 99.92 MPa and the Young's modulus increased from 0.76 GPa to 4.16 GPa. This work provided a promising pathway for manufacturing high performance and environmental-friendly all-cellulose nanocomposites.

  3. Microwave-Assisted Hydrothermal Synthesis of Cellulose/Hydroxyapatite Nanocomposites

    Directory of Open Access Journals (Sweden)

    Lian-Hua Fu

    2016-09-01

    Full Text Available In this paper, we report a facile, rapid, and green strategy for the synthesis of cellulose/hydroxyapatite (HA nanocomposites using an inorganic phosphorus source (sodium dihydrogen phosphate dihydrate (NaH2PO4·2H2O, or organic phosphorus sources (adenosine 5′-triphosphate disodium salt (ATP, creatine phosphate disodium salt tetrahydrate (CP, or D-fructose 1,6-bisphosphate trisodium salt octahydrate (FBP through the microwave-assisted hydrothermal method. The effects of the phosphorus sources, heating time, and heating temperature on the phase, size, and morphology of the products were systematically investigated. The experimental results revealed that the phosphate sources played a critical role on the phase, size, and morphology of the minerals in the nanocomposites. For example, the pure HA was obtained by using NaH2PO4·2H2O as phosphorus source, while all the ATP, CP, and FBP led to the byproduct, calcite. The HA nanostructures with various morphologies (including nanorods, pseudo-cubic, pseudo-spherical, and nano-spherical particles were obtained by varying the phosphorus sources or adjusting the reaction parameters. In addition, this strategy is surfactant-free, avoiding the post-treatment procedure and cost for the surfactant removal from the product. We believe that this work can be a guidance for the green synthesis of cellulose/HA nanocomposites in the future.

  4. Cellulose ethanol is ready to go

    Energy Technology Data Exchange (ETDEWEB)

    Hladik, M. [Iogen Corp., Ottawa, ON (Canada)

    2006-07-01

    Ottawa-based Iogen Corporation is a leader in industrial biotechnology with a focus on cellulose-based enzyme technology. The company designed and operates the world's first and largest cellulose ethanol demonstration facility making ethanol from biomass. This presentation described Iogen's cellulose ethanol demonstration facility and outlined the innovative process in which enzymes prepare the plant fibres for fermentation, distillation and finally conversion to cellulose ethanol fuel. Hydrolysis and fermentation are achieved using a multi-stage hydrolysis process. It is anticipated that biorefineries will use the residues from locally grown agriculture to produce the ethanol, but stakeholder alliances will have to be built in order to form the elements of commercialization. Feedstocks, government policy, infrastructure issues, investment climate and ethanol sales all contribute to the success of a commercial plant. An assessment of preliminary global feedstock availability was presented with reference to total wheat, coarse grains, barley, oats, rye, sorghum, rice straw and sugar cane production. To date, the use of cellulose ethanol fuel has been demonstrated in vehicle trials in Bonn, Germany, as well as fleet vehicles operated by Natural Resources Canada and Agriculture Canada. Sample feedstock basins in Germany, Canada and the United States were highlighted. The supply of cellulose feedstock is large enough to contribute significantly to reductions in fossil fuel consumption. The United States Department of Energy claims that cellulose ethanol could displace over 30 per cent of the current petroleum consumption in the United States, and that land resources in the United States are capable of producing a sustainable supply of biomass. However, technology, financing and government policies are the factors which currently affect the commercialization of emerging technologies. tabs., figs.

  5. Production of Cellulosic Polymers from Agricultural Wastes

    Directory of Open Access Journals (Sweden)

    A. U. Israel

    2008-01-01

    Full Text Available Cellulosic polymers namely cellulose, di-and triacetate were produced from fourteen agricultural wastes; Branch and fiber after oil extraction from oil palm (Elais guineensis, raffia, piassava, bamboo pulp, bamboo bark from raphia palm (Raphia hookeri, stem and cob of maize plant (Zea mays, fruit fiber from coconut fruit (Cocos nucifera, sawdusts from cotton tree (Cossypium hirsutum, pear wood (Manilkara obovata, stem of Southern gamba green (Andropogon tectorus, sugarcane baggase (Saccharium officinarum and plantain stem (Musa paradisiaca. They were subjected to soda pulping and hypochlorite bleaching system. Results obtained show that pulp yield from these materials were: 70.00, 39.59, 55.40, 86.00, 84.60, 80.00, 40.84, 81.67, 35.70, 69.11, 4.54, 47.19, 31.70 and 52.44% respectively. The pulps were acetylated with acetic anhydride in ethanoic acid catalyzed by conc. H2SO4 to obtain cellulose derivatives (Cellulose diacetate and triacetate. The cellulose diacetate yields were 41.20, 17.85, 23.13, 20.80, 20.23, 20.00, 39.00, 44.00, 18.80, 20.75, 20.03, 41.20, 44.00, and 39.00% respectively while the results obtained as average of four determinations for cellulose triacetate yields were: 52.00, 51.00, 43.10, 46.60, 49.00, 35.00, 40.60, 54.00, 57.50, 62.52, 35.70. 52.00, 53.00 and 38.70% respectively for all the agricultural wastes utilized. The presence of these cellulose derivatives was confirmed by a solubility test in acetone and chloroform.

  6. Effects of heat treatment on chitosan nanocomposite film reinforced with nanocrystalline cellulose and tannic acid.

    Science.gov (United States)

    Rubentheren, V; Ward, Thomas A; Chee, Ching Yern; Nair, Praveena; Salami, Erfan; Fearday, Christopher

    2016-04-20

    This article presents an analysis of the influence of heat treatment on chitosan nanocomposite film. A series of samples comprising: pure chitosan film, chitosan film embedded with nanocrystalline cellulose (NCC), chitosan film crosslinked with tannic acid and chitosan film with a blend of NCC and tannic acid were heat treated using a convection oven. Fourier-transform-infrared spectroscopy (FTIR) and X-ray diffraction test (XRD) shows the changes in chemical interaction of the heat treated films. The heat treated films show significant improvements in moisture absorption. Tensile strength and Young's Modulus were increased up to 7MPa and 259MPa, respectively when the samples were subjected to heat treatment. For the NCC particles, a transmission electron microscope (TEM) was used to inspect the structural properties of cellulose particle in suspension form.

  7. Particle Pollution

    Science.gov (United States)

    ... Your Health Particle Pollution Public Health Issues Particle Pollution Recommend on Facebook Tweet Share Compartir Particle pollution ... see them in the air. Where does particle pollution come from? Particle pollution can come from two ...

  8. Miniaturization of cellulose fibers and effect of addition on the mechanical and barrier properties of hydroxypropyl methylcellulose

    Science.gov (United States)

    Cellulose fibers were miniaturized by microfluidics technology and incorporated in hydroxypropyl methylcellulose (HPMC) films to study the effect of the addition of such fibers on the mechanical and barrier properties of HPMC films suitable for food packaging applications. The particle size of the f...

  9. Analysis of Organic matter from cloud particles

    Science.gov (United States)

    Bank, Shelton; Castillo, Raymond

    1987-03-01

    Organic matter collected from filtration of two separate cloud events was analysed by Fourier Transform Infrared Spectroscopy. Particles collected from different size filters were separated by color and each type of particle gave rise to a characteristic spectrum. The major constituents were identified as complex proteins and cellulose. Additionally, some degraded material (likely protein) and an unidentified orange-brown material were present. Finally some trace components were identified as wax, oil, silicon oil, polyvinyl chloride, calcium carbonate, clay, sand and polyethylene.

  10. Isolation and characterization of two cellulose morphology mutants of Gluconacetobacter hansenii ATCC23769 producing cellulose with lower crystallinity.

    Directory of Open Access Journals (Sweden)

    Ying Deng

    Full Text Available Gluconacetobacter hansenii, a Gram-negative bacterium, produces and secrets highly crystalline cellulose into growth medium, and has long been used as a model system for studying cellulose synthesis in higher plants. Cellulose synthesis involves the formation of β-1,4 glucan chains via the polymerization of glucose units by a multi-enzyme cellulose synthase complex (CSC. These glucan chains assemble into ordered structures including crystalline microfibrils. AcsA is the catalytic subunit of the cellulose synthase enzymes in the CSC, and AcsC is required for the secretion of cellulose. However, little is known about other proteins required for the assembly of crystalline cellulose. To address this question, we visually examined cellulose pellicles formed in growth media of 763 individual colonies of G. hansenii generated via Tn5 transposon insertion mutagenesis, and identified 85 that produced cellulose with altered morphologies. X-ray diffraction analysis of these 85 mutants identified two that produced cellulose with significantly lower crystallinity than wild type. The gene disrupted in one of these two mutants encoded a lysine decarboxylase and that in the other encoded an alanine racemase. Solid-state NMR analysis revealed that cellulose produced by these two mutants contained increased amounts of non-crystalline cellulose and monosaccharides associated with non-cellulosic polysaccharides as compared to the wild type. Monosaccharide analysis detected higher percentages of galactose and mannose in cellulose produced by both mutants. Field emission scanning electron microscopy showed that cellulose produced by the mutants was unevenly distributed, with some regions appearing to contain deposition of non-cellulosic polysaccharides; however, the width of the ribbon was comparable to that of normal cellulose. As both lysine decarboxylase and alanine racemase are required for the integrity of peptidoglycan, we propose a model for the role of

  11. Antimicrobial effect of silver-impregnated cellulose: potential for antimicrobial therapy

    OpenAIRE

    Ostler Erik; Kwon Soonjo; Kim Juyoung

    2009-01-01

    Abstract Background Silver has long been known to have antimicrobial activity. To incorporate this property into multiple applications, a silver-impregnated cellulose (SIC) with low cytotoxicity to human cells was developed. SIC differs from other silver treatment methods in that the leaching of silver particles is non-existent and the release of ionic silver is highly controlled. Results Candida albicans, Micrococcus luteu, Pseudomonas putida, and Escherichia coli were used for antimicrobial...

  12. Lyocell Fiber-Reinforced Cellulose Ester Composites-Manufacturing Considerations and Properties.

    OpenAIRE

    1999-01-01

    Biodegradable thermoplastic composites were prepared using high modulus lyocell fibers and cellulose acetate butyrate (CAB). Two reinforcement fiber types: fabric and continuous fiber tow were used. Fabric had advantages of uniform alignment and easier processing, but lacked the use as a unidirectional reinforcement and a continuous method of matrix application. Three different matrix application methods were screened for both fiber types. Matrix application by suspension of particles in wate...

  13. Electrically conductive bacterial cellulose composite membranes produced by the incorporation of graphite nanoplatelets in pristine bacterial cellulose membranes

    Directory of Open Access Journals (Sweden)

    T. Zhou

    2013-09-01

    Full Text Available Graphite nanoplatelets (GNPs were utilized to improve the electrical conductivity of pristine bacterial cellulose (BC membranes. By physical and chemical methods, flake-shaped GNPs, weaving through the surface layer of web-like cellulose nanofibrils, were indeed fixed or trapped by the adjacent nanofibrils in the BC surface network, for comparison, rod-shaped multi-walled carbon nanotubes (MWCNTs were homogeneously inserted into BC membrane through the pore structures and tunnels within the BC membrane. Strong physical and chemical interaction exists between the BC nanofibrils and the particles of GNP or MWCNT even after 15 h sonication. BC membrane with 8.7 wt% incorporated GNPs reached the maximum electrical conductivity of 4.5 S/cm, while 13.9 wt% MWCNT/BC composite membrane achieved the maximum electrical conductivity of 1.2 S/cm. Compared with one dimensional (1-D MWCNTs, as long as GNPs inserted into BC membranes, the 2-D reinforcement of GNPs was proven to be more effective in improving the electrical conductivity of BC membranes thus not only break the bottleneck of further improvement of the electrical conductivity of BC-based composite membranes but also broaden the applications of BC and GNPs.

  14. PREPARATION AND CHARACTERIZATION OF BAMBOO NANOCRYSTALLINE CELLULOSE

    Directory of Open Access Journals (Sweden)

    Mengjiao Yu,

    2012-02-01

    Full Text Available Nanocrystalline cellulose (NCC has many potential applications because of its special properties. In this paper, NCC was prepared from bamboo pulp. Bamboo pulp was first pretreated with sodium hydroxide, followed by hydrolysis with sulfuric acid. The concentration of sulfuric acid and the hydrolysis time on the yield of NCC were studied. The results showed that sulfuric acid concentration had larger influence than the hydrolysis time on the yield of NCC. When the temperature was 50oC, the concentration of sulfuric acid was 48wt% and the reaction time was 30 minutes, a high quality of nanocrystalline cellulose was obtained; under these conditions, the length of the nanocrystalline cellulose ranged from 200 nm to 500 nm, the diameter was less than 20 nm, the yield was 15.67wt%, and the crystallinity was 71.98%, which is not only higher than those of cellulose nanocrystals prepared from some non-wood materials, but also higher than bamboo cellulose nanocrystals prepared by other methods.

  15. Cellulose multilayer Membranes manufacture with Ionic liquid

    KAUST Repository

    Livazovic, Sara

    2015-05-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. By these methods porous supports could be easily coated with semi-crystalline cellulose. The membranes were hydrophilic with contact angles as low as 22.0°, molecular weight cut-off as low as 3000 g mol-1 with corresponding water permeance of 13.8 Lm−2 h−1 bar−1. Self-standing cellulose membranes were also manufactured without porous substrate, using only ionic liquid as green solvent. This membrane was insoluble in water, tetrahydrofuran, hexane, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and N,N-dimethylacetamide.

  16. Silicone Rubber and Microcrystalline Cellulose Composites with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Virginija JANKAUSKAITĖ

    2014-04-01

    Full Text Available The goal of this study was to create polydimethylsiloxane (PDMS and microcrystalline cellulose (MCC composites with high mechanical properties and antimicrobial activity. Vinyl-terminated PDMS was mixed with bifunctional filler, which combines MCC stiffness and antimicrobial properties of silver nanoparticles. To provide antimicrobial properties the silver nanoparticles in situ were synthesized by chemical reducing method in MCC aqueous suspension. Silver nanoparticles (AgNPs concentration deposited on MCC particles surface was varied. The morphology, antimicrobial activity and mechanical properties of PDMS/MCC composites and their components have been investigated. It was shown that the combination of MCC/AgNPs as a filler and PDMS as matrix advantages bring multifunctional properties to polymer matrix composite. DOI: http://dx.doi.org/10.5755/j01.ms.20.1.4397

  17. Highly ordered cellulose II crystalline regenerated from cellulose hydrolyzed by 1-butyl-3-methylimidazolium chloride.

    Science.gov (United States)

    Ahn, Yongjun; Song, Younghan; Kwak, Seung-Yeop; Kim, Hyungsup

    2016-02-10

    This research focused on the preparation of highly ordered cellulose II crystalline by cellulose hydrolysis in ionic liquid, and the influence of molecular mobility on recrystallization of cellulose. The molar mass of cellulose was controlled by hydrolysis using 1-butyl-3-methylimidazolium chloride (BmimCl). The molecular mobility of cellulose dissolved in BmimCl was characterized by rheological properties. After characterization of cellulose solution and regeneration, change of molar mass and conversion to crystalline were monitored using gel-permeation chromatography and powder X-ray diffraction, respectively. The molar mass of the cellulose in BmimCl was remarkably decreased with an increase in duration time, resulting in better mobility and a lower conformational constraint below critical molar mass. The decrease in molar mass surprisingly increased the crystallinity up to ∼ 85%, suggesting a recrystallization rate dependence of the mobility. The correlation between the mobility and recrystallization rate represented quit different behavior above and below a critical molar mass, which strongly demonstrated to the effect of mobility on the conversion of amorphous state to crystalline structure.

  18. Segal crystallinity index revisited by the simulation of X-ray diffraction patterns of cotton cellulose Iβ and cellulose II.

    Science.gov (United States)

    Nam, Sunghyun; French, Alfred D; Condon, Brian D; Concha, Monica

    2016-01-01

    The Segal method estimates the amorphous fraction of cellulose Iβ materials simply based on intensity at 18° 2θ in an X-ray diffraction pattern and was extended to cellulose II using 16° 2θ intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and the degree of polymorphic conversion, we simulated the diffraction patterns of cotton celluloses (Iβ and II) and compared the simulated amorphous fractions with the Segal values. The diffraction patterns of control and mercerized cottons, respectively, were simulated with perfect crystals of cellulose Iβ (1.54° FWHM) and cellulose II (2.30° FWHM) as well as 10% and 35% amorphous celluloses. Their Segal amorphous fractions were 15% and 31%, respectively. The higher Segal amorphous fraction for control cotton was attributed to the peak overlap. Although the amorphous fraction was set in the simulation, the peak overlap induced by the increase of FWHM further enhanced the Segal amorphous intensity of cellulose Iβ. For cellulose II, the effect of peak overlap was smaller; however the lower reflection of the amorphous cellulose scattering in its Segal amorphous location resulted in smaller Segal amorphous fractions. Despite this underestimation, the relatively good agreement of the Segal method with the simulation for mercerized cotton was attributed to the incomplete conversion to cellulose II. The (1-10) and (110) peaks of cellulose Iβ remained near the Segal amorphous location of cellulose II for blends of control and mercerized cotton fibers.

  19. Nanocrystalline cellulose from coir fiber: preparation, properties, and applications

    Science.gov (United States)

    Nanocrystalline cellulose derived from various botanical sources offers unique and potentially useful characteristics. In principle, any cellulosic material can be considered as a potential source of a nanocrystalline material, including crops, crop residues, and agroindustrial wastes. Because of t...

  20. Tissue engineering scaffolds electrospun from cotton cellulose.

    Science.gov (United States)

    He, Xu; Cheng, Long; Zhang, Ximu; Xiao, Qiang; Zhang, Wei; Lu, Canhui

    2015-01-22

    Nonwovens of cellulose nanofibers were fabricated by electrospinning of cotton cellulose in its LiCl/DMAc solution. The key factors associated with the electrospinning process, including the intrinsic properties of cellulose solutions, the rotating speed of collector and the applied voltage, were systematically investigated. XRD data indicated the electrospun nanofibers were almost amorphous. When increasing the rotating speed of the collector, preferential alignment of fibers along the drawing direction and improved molecular orientation were revealed by scanning electron microscope and polarized FTIR, respectively. Tensile tests indicated the strength of the nonwovens along the orientation direction could be largely improved when collected at a higher speed. In light of the excellent biocompatibility and biodegradability as well as their unique porous structure, the nonwovens were further assessed as potential tissue engineering scaffolds. Cell culture experiments demonstrated human dental follicle cells could proliferate rapidly not only on the surface but also in the entire scaffold.

  1. ADSORPTION AND RELEASING PROPERTIES OF BEAD CELLULOSE

    Institute of Scientific and Technical Information of China (English)

    A. Morales; E. Bordallo; V. Leon; J. Rieumont

    2004-01-01

    The adsorption of some dyes on samples of bead cellulose obtained in the Unit of Research-Production "Cuba 9"was studied. Methylene blue, alizarin red and congo red fitted the adsorption isotherm of Langmuir. Adsorption kinetics at pH = 6 was linear with the square root of time indicating the diffusion is the controlling step. At pH = 12 a non-Fickian trend was observed and adsorption was higher for the first two dyes. Experiments carried out to release the methylene blue occluded in the cellulose beads gave a kinetic behavior of zero order. The study of cytochrome C adsorption was included to test a proteinic material. Crosslinking of bead cellulose was performed with epichlorohydrin decreasing its adsorption capacity in acidic or alkaline solution.

  2. Chemical genetics to examine cellulose biosynthesis

    Directory of Open Access Journals (Sweden)

    Seth eDebolt

    2013-01-01

    Full Text Available Long-term efforts to decode plant cellulose biosynthesis via molecular genetics and biochemical strategies are being enhanced by the ever-expanding scale of omics technologies. An alternative approach to consider are the prospects for inducing change in plant metabolism using exogenously supplied chemical ligands. Cellulose biosynthesis inhibitors (CBI have been identified among known herbicides, during diverse combinatorial chemical libraries screens, and natural chemical screens from microbial agents. In this review, we summarize the current knowledge of the inhibitory effects of CBIs and further group them by how they influence fluorescently tagged cellulose synthase A (CESA proteins. Additional attention is paid to the continuing development of the CBI toolbox to explore the cell biology and genetic mechanisms underpinning effector molecule activity.

  3. Novel Nitrocellulose Made from Bacterial Cellulose

    Science.gov (United States)

    Sun, Dong-Ping; Ma, Bo; Zhu, Chun-Lin; Liu, Chang-Sheng; Yang, Jia-Zhi

    2010-04-01

    Nitrocellulose (NC) is useful in several industrial segments, especially in the production of gun, rocket, and missile propellants. The conventional way to prepare NC is done through the nitration of plant cellulose with nitric acid. In this work, bacterial cellulose nitrate (NBC) is synthesized by bacterial cellulose (BC) and nitro-sulfric acid under heterogeneous conditions. NBC with the degree of substitution (DS) of 1-2.85 was obtained, and the effects of sulfuric to nitric ratio, reaction temperature, and reaction time on the value of DS of NBC are discussed. The samples are also characterized by elemental analysis, thermal analysis, Fourier transform infrared (FT-IR) spectroscopy, and X-ray diffraction.

  4. African perspective on cellulosic ethanol production

    DEFF Research Database (Denmark)

    Bensah, Edem Cudjoe; Kemausuor, Francis; Miezah, Kodwo;

    2015-01-01

    to ethanol, among others. While the industrialized and some emerging countries are gradually breaking grounds in cellulosic ethanol, most African countries have made little effort in research and development even though the continent is rich in lignocellulosic biomass. The paper estimates residues from......A major challenge to commercial production of cellulosic ethanol pertains to the cost-effective breakdown of the complex and recalcitrant structure of lignocellulose into its components via pretreatment, the cost of enzymes for hydrolysis and fermentation, and the conversion rate of C5 sugars...... widely available crops and municipal waste and determines their respective theoretical ethanol potential (around 22 billion litres annually). It further reviews stages involved in the production of cellulosic ethanol, focussing on processing methods that can be adapted to current situation in most...

  5. POLYETHERSULFONE COMPOSITE MEMBRANE BLENDED WITH CELLULOSE FIBRILS

    Directory of Open Access Journals (Sweden)

    Ping Qu

    2010-09-01

    Full Text Available Polyethersulfone (PES is a common material used for ultrafiltration (UF membranes, which has good chemical resistance, high mechanical properties, and wide temperature tolerances. The hydrophobic property of the PES membrane seriously limits its application. Cellulose fibrils are composed of micro-sized and nano-sized elements, which have high hydrophilicity, strength, and biodegradation. A composite membrane was prepared by the phase inversion induced by an immersion process. The characteristics of the composite membrane were investigated with Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and atomic force microscopy (AFM. The pure water flux of the composite membrane increased dramatically with the increase of cellulose firbils. Mean pore size and porosity were significantly increased. Both mechanical properties and hydrophilicity were enhanced due to the addition of the cellulose firbils.

  6. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  7. Prospects for Irradiation in Cellulosic Ethanol Production

    Directory of Open Access Journals (Sweden)

    Anita Saini

    2015-01-01

    Full Text Available Second generation bioethanol production technology relies on lignocellulosic biomass composed of hemicelluloses, celluloses, and lignin components. Cellulose and hemicellulose are sources of fermentable sugars. But the structural characteristics of lignocelluloses pose hindrance to the conversion of these sugar polysaccharides into ethanol. The process of ethanol production, therefore, involves an expensive and energy intensive step of pretreatment, which reduces the recalcitrance of lignocellulose and makes feedstock more susceptible to saccharification. Various physical, chemical, biological, or combined methods are employed to pretreat lignocelluloses. Irradiation is one of the common and promising physical methods of pretreatment, which involves ultrasonic waves, microwaves, γ-rays, and electron beam. Irradiation is also known to enhance the effect of saccharification. This review explains the role of different radiations in the production of cellulosic ethanol.

  8. Magnetic alignment and patterning of cellulose fibers

    Directory of Open Access Journals (Sweden)

    Fumiko Kimura and Tsunehisa Kimura

    2008-01-01

    Full Text Available The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved

  9. Magnetic alignment and patterning of cellulose fibers

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Fumiko; Kimura, Tsunehisa [Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: tkimura@kais.kyoto-u.ac.jp

    2008-04-01

    The alignment and patterning of cellulose fibers under magnetic fields are reported. Static and rotating magnetic fields were used to align cellulose fibers with sizes ranging from millimeter to nanometer sizes. Cellulose fibers of the millimeter order, which were prepared for papermaking, and much smaller fibers with micrometer to nanometer sizes prepared by the acid hydrolysis of larger ones underwent magnetic alignment. Under a rotating field, a uniaxial alignment of fibers was achieved. The alignment was successfully fixed by the photopolymerization of a UV-curable resin precursor used as matrix. A monodomain chiral nematic film was prepared from an aqueous suspension of nanofibers. Using a field modulator inserted in a homogeneous magnetic field, simultaneous alignment and patterning were achieved.

  10. Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

    Institute of Scientific and Technical Information of China (English)

    YUAN Xia; FANG Kuan-jun

    2006-01-01

    Waterborne nanoscale carbon black dispersion (NCBD) was widely used in inkjet printing, spun-dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose (CMC) as dispersant.Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black (CB) particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it increased by ultrasonic with the increase of CMC viscosity. Ultrasonic is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size obviously decreased with increasing ultrasonic time and arrived at about 160 nm for 60 min. In addition, oxidation with 2 mol/L of H2O2 and 0.2 wt% of CMC300 reduced CB particle size to 160 nm at 90℃ for 2.5 h.

  11. Alexa fluor-labeled fluorescent cellulose nanocrystals for bioimaging solid cellulose in spatially structured microenvironments.

    Science.gov (United States)

    Grate, Jay W; Mo, Kai-For; Shin, Yongsoon; Vasdekis, Andreas; Warner, Marvin G; Kelly, Ryan T; Orr, Galya; Hu, Dehong; Dehoff, Karl J; Brockman, Fred J; Wilkins, Michael J

    2015-03-18

    Methods to covalently conjugate Alexa Fluor dyes to cellulose nanocrystals, at limiting amounts that retain the overall structure of the nanocrystals as model cellulose materials, were developed using two approaches. In the first, aldehyde groups are created on the cellulose surfaces by reaction with limiting amounts of sodium periodate, a reaction well-known for oxidizing vicinal diols to create dialdehyde structures. Reductive amination reactions were then applied to bind Alexa Fluor dyes with terminal amino-groups on the linker section. In the absence of the reductive step, dye washes out of the nanocrystal suspension, whereas with the reductive step, a colored product is obtained with the characteristic spectral bands of the conjugated dye. In the second approach, Alexa Fluor dyes were modified to contain chloro-substituted triazine ring at the end of the linker section. These modified dyes then were reacted with cellulose nanocrystals in acetonitrile at elevated temperature, again isolating material with the characteristic spectral bands of the Alexa Fluor dye. Reactions with Alexa Fluor 546 are given as detailed examples, labeling on the order of 1% of the total glucopyranose rings of the cellulose nanocrystals at dye loadings of ca. 5 μg/mg cellulose. Fluorescent cellulose nanocrystals were deposited in pore network microfluidic structures (PDMS) and proof-of-principle bioimaging experiments showed that the spatial localization of the solid cellulose deposits could be determined, and their disappearance under the action of Celluclast enzymes or microbes could be observed over time. In addition, single molecule fluorescence microscopy was demonstrated as a method to follow the disappearance of solid cellulose deposits over time, following the decrease in the number of single blinking dye molecules with time instead of fluorescent intensity.

  12. Processing of cellulose for the advancement of biofuels

    Science.gov (United States)

    Watson, Brian James

    2011-12-01

    The enzymatic degradation of cellulose polymers is currently a rate-limiting step in the bioconversion of biomass to biofuels. Cellulose polymers self assemble to form crystalline structures stabilized by a complex network of intermolecular interactions such as hydrogen bonding. The network of interactions in crystalline cellulose (cellulose nanostructure) poses an energy barrier that limits enzymatic degradation as apparent from the activity of Cel5H. To improve the degradability of cellulose the intermolecular interactions must be disrupted. The interactions of the cellulose nanostructure prevent solubilization by water and most other common solvents, but some organic solvents aid degradation of cellulose suggesting they influence cellulose nanostructure. The objective of this work is to understand the influence of solvents on cellulose nanostructure with the goal of improving the degradability of cellulose nanostructure using solvents. To understand solvent interaction with cellulose, phosphoric acid was used to first solubilize cellulose (PAS cellulose) followed by adding an organic liquid or water to wash the phosphate from the system. The Flory Huggins theory was used to predict wash liquids that could favorably interact with cellulose. A favorable wash liquid was predicted to prevent the reformation of crystalline domains to yield a disrupted cellulose nanostructure, which should be more degradable. Low molecular weight alcohols and glycols were calculated to be favorable wash liquids. Washing PAS cellulose with the predicted favorable liquids yielded semi-transparent gel-like materials compared to the opaque white precipitate formed when water or unfavorable solvents were used in the wash. Fractal analysis of small angle neutron scattering (SANS) of these apparent gels indicated cellulose polymers likely have the properties of clustered rods. This partial disruption increased degradability relative to the water washed PAS cellulose. The apparent rod

  13. Cellulose nanoparticles: photoacoustic contrast agents that biodegrade to simple sugars

    Science.gov (United States)

    Jokerst, Jesse V.; Bohndiek, Sarah E.; Gambhir, Sanjiv S.

    2014-03-01

    In photoacoustic imaging, nanoparticle contrast agents offer strong signal intensity and long-term stability, but are limited by poor biodistribution and clearance profiles. Conversely, small molecules offer renal clearance, but relatively low photoacoustic signal. Here we describe a cellulose-based nanoparticle with photoacoustic signal superior to gold nanorods, but that undergoes enzymatic cleavage into constituent glucose molecules for renal clearance. Cellulose nanoparticles (CNPs) were synthesized through acidic cleavage of cellulose linters and purified with centrifugation. TEM indicated that the nanoparticles were 132 +/- 46 nm; the polydispersity index was 0.138. Ex vivo characterization showed a photoacoustic limit of detection of 0.02 mg/mL CNPs, and the photoacoustic signal of CNPs was 1.5- to 3.0-fold higher than gold nanorods (also at 700 nm resonance) on a particle-to-particle basis. Cell toxicity assays suggested that overnight doses below 0.31 mg/mL CNPs produced no significant (p>0.05) impact on cell metabolism. Intravenous doses up to 0.24 mg were tolerated well in nude mice. Subcutaneous and orthotopic tumor xenografts of the OV2008 ovarian cancer cell line were then created in nude mice. Data was collected with a Nexus128 scanner from Endra LifeSciences. Spectral data used a LAZR system from Visualsonics both at 700 nm excitation. We injected CNPs (0.024 mg, 0.048 mg, and 0.80 mg) via tail vein and showed that the tumor photoacoustic signal reached maximum increase between 10 and 20 minutes. All injected concentrations were statistically (p0.96 suggesting quantitative signal. CNP biodegradation was demonstrated ex vivo with a glucose assay. CNPs in the presence of cellulase were reduced to free glucose in under than four hours. The glucose concentration before addition of cellulase was not detectable, but increased to 92.1 μg/mL in four hours. CNPs in the absence of cellulase did not produce glucose. Small fragments of nanoparticle in the

  14. The Synthesis of a Novel Cellulose Physical Gel

    OpenAIRE

    Jiufang Duan; Xiaojian Zhang; Jianxin Jiang; Chunrui Han; Jun Yang; Liujun Liu; Hongyun Lan; Daozhan Huang

    2014-01-01

    Cellulose possessing β-cyclodextrin (β-CD) was used as a host molecule and cellulose possessing ferrocene (Fc) as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC), ultraviolet spectroscopy (UV), and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodi...

  15. Development of hierarchical cellulosic reinforcement for polymer composites

    OpenAIRE

    2014-01-01

    Cellulose is an environmentally friendly material which is obtainable in vast quantities, since it is present in every plant. Cellulosic fibers are commercially found in two forms: natural (flax, hemp, cotton, sisal, wood, etc.) and regenerated cellulose fibers (RCF). The biodegradability, the morphological and mechanical properties make these fibers a good alternative to the synthetic reinforcement (e.g. glass fibers). However, as all other cellulosic fibers these materials also have similar...

  16. New Solvents for Cellulose. II. Ethylenediamine/Thiocyanate Salt System

    OpenAIRE

    HATTORI, Kazuyuki; ABE, Emiko; Yoshida, Takashi; CUCULO, John A.; 服部,和幸; 吉田, 孝

    2004-01-01

    The ethylenediamine/thiocyanate salt system was found to be a new solvent for cellulose. The solubility, dissolution behavior, solution properties, and cellulose recovered from the solutions were investigated. The dissolution took place at room temperature, and the maximum solubility achieved was 16% (w/w) for cellulose of DP210 in the ethylenediamine/sodium thiocyanate 54/46 (w/w).The dependence of cellulose solubility on DP is also described. Tracing the dissolution behavior of the cellulos...

  17. Mercerization and Enzymatic Pretreatment of Cellulose in Dissolving Pulps

    OpenAIRE

    2013-01-01

    This thesis deals with the preparation of chemically and/or enzymatically modified cellulose. This modification can be either irreversible or reversible. Irreversible modification is used to prepare cellulose derivatives as end products, whereas reversible modification is used to enhance solubility in the preparation of regenerated cellulose. The irreversible modification studied here was the preparation of carboxymethyl cellulose (CMC) using extended mercerization of a spruce dissolving pulp...

  18. 21 CFR 172.872 - Methyl ethyl cellulose.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl ethyl cellulose. 172.872 Section 172.872... CONSUMPTION Multipurpose Additives § 172.872 Methyl ethyl cellulose. The food additive methyl ethyl cellulose... a cellulose ether having the general formula [C6H(10 -x-y)O5(CH3)x(C2H5)y]n, where x is the...

  19. Fabrication of water-repellent cellulose fiber coated with magnetic nanoparticles under supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Xu Shengjie; Shen Danping; Wu Peiyi, E-mail: peiyiwu@fudan.edu.cn [Fudan University, State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials (China)

    2013-04-15

    Hematite nanoparticle-coated magnetic composite fiber was prepared in supercritical carbon dioxide (scCO{sub 2}). With the help of scCO{sub 2}, cellulose did not need to be dissolved and regenerated and it could be in any form (e.g., cotton wool, filter paper, textile, etc.). The penetrating and swelling effect of scCO{sub 2}, the slowing reaction rate of weak alkalis, and the template effect of cellulose fibers were discovered to be the key factors for the fabrication of ordered cellulose/Fe{sub 2}O{sub 3} composite fibers. The structures of the composite fibers as well as the layers of Fe{sub 2}O{sub 3} particles were characterized by means of scanning/transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman investigation. It was found that {alpha}-Fe{sub 2}O{sub 3} granules which ranged from 30 to 85 nm with average diameter around 55 nm would be generated on the surface of cellulose fibers via potassium acetate, while irregular square prisms (ranged from 200 to 600 nm) which were composed of smaller nanoparticles ({approx}10 nm) would be fabricated via urea. And, the obtained composite was highly water repellent with superparamagnetic or ferromagnetic properties.

  20. Properties of modified carboxymethyl cellulose and its use as bioactive compound.

    Science.gov (United States)

    Basta, Altaf H; El-Saied, Houssni; El-Deftar, Mervat M; El-Henawy, Ahmed A; El-Sheikh, Hussein H; Abdel-Shakour, Essam H; Hasanin, Mohamed S

    2016-11-20

    The present study deals with synthesizing novel cellulose derivative, from modifying the carboxymethyl cellulose with amino phenylpropanoic acid (CMC-APP). The synthesized CMC-APP was evaluated as biological and anti-cancer active compound. The molecular structures of this active compound were built using the HyperChem program 7.5, together with conventional analysis (nitrogen content, FT-IR, and non-isothermal TGA analysis). Optimizing the CMC/APPA ratio was carried out as preliminary assessment step, via undetected antimicrobial activity measurement. The TEM study showed that, the synthesized cellulose CMC-APP derivative in the nano-scale particle size (range from 12.5 to 89.3nm). Among all the tested microorganisms and MCF-7 breast cancer cells, the synthesized nano-cellulose derivative is possible used as safety medicine for microbial infections and cancers. The minimal inhibitory concentration (MIC) for Gram-positive bacteria, and gram-negative bacteria are 48.82μg/mL and 97μg/mL, respectively. While, the unicellular fungi and filamentous fungi are 12.2μg/mL and 97.65μg/mL, respectively. The cytotoxic index (IC50) for MCF-7 breast cancers is 50μg/mL. Moreover, the computational study of ADMET (absorption, distribution, metabolism, elimination and toxic) properties, of the molecules showed that, this investigated nano-compound is good oral bioavailability.

  1. Electrospinning cellulose based nanofibers for sensor applications

    Science.gov (United States)

    Nartker, Steven

    2009-12-01

    Bacterial pathogens have recently become a serious threat to the food and water supply. A biosensor based on an electrochemical immunoassay has been developed for detecting food borne pathogens, such as Escherichia coli (E. coli) O157:H7. These sensors consist of several materials including, cellulose, cellulose nitrate, polyaniline and glass fibers. The current sensors have not been optimized in terms of microscale architecture and materials. The major problem associated with the current sensors is the limited concentration range of pathogens that provides a linear response on the concentration conductivity chart. Electrospinning is a process that can be used to create a patterned fiber mat design that will increase the linear range and lower the detection limit of these sensors by improving the microscale architecture. Using the electrospinning process to produce novel mats of cellulose nitrate will offer improved surface area, and the cellulose nitrate can be treated to further improve chemical interactions required for sensor activity. The macro and micro architecture of the sensor is critical to the performance of the sensors. Electrospinning technology can be used to create patterned architectures of nanofibers that will enhance sensor performance. To date electrospinning of cellulose nitrate has not been performed and optimization of the electrospinning process will provide novel materials suitable for applications such as filtration and sensing. The goal of this research is to identify and elucidate the primary materials and process factors necessary to produce cellulose nitrate nanofibers using the electrospinning process that will improve the performance of biosensors. Cellulose nitrate is readily dissolved in common organic solvents such as acetone, tetrahydrofuran (THF) and N,N dimethylformamide (DMF). These solvents can be mixed with other latent solvents such as ethanol and other alcohols to provide a solvent system with good electrospinning behavior

  2. Preparation of zeolite covered cellulose fibers

    Energy Technology Data Exchange (ETDEWEB)

    Mintova, S.; Valtchev, V. [Institute of Applied Mineralogy, Sofia (Bulgaria)

    1995-12-01

    Membrane separation has proved to be an important technology in chemical industry. That is why the design of different type of zeolite containing membranes has received much attention during the last decade. Zeolite containing filters and membranes were prepared by embedding zeolite crystals with adhesive substances in the cellulose matrix. This communication discussed the preparation of zeolite containing cellulose materials by in situ crystallization. Discussed axe: (1) the effect of the vegetal fiber structure and chemical composition (2) the effect of the type of the zeolite coating; (3) the effect of the mechanical and chemical treatment of the fibers on the process of the fiber zeolite coating.

  3. Cellulose hydrolysis by immobilized Trichoderma reesei cellulase.

    Science.gov (United States)

    Jones, Paetrice O; Vasudevan, Palligarnai T

    2010-01-01

    Cellulose hydrolysis by immobilized Trichoderma reesei cellulase in the presence of a low viscosity ionic liquid, 1-ethyl-3-methylimidazolium diethyl phosphate (EMIM-DEP), was investigated. Preparation of the carrier-free immobilized cellulase was optimized with respect to concentration of the cross-linker and the type of precipitant. The addition of 2% (v/v) EMIM-DEP during hydrolysis gave an initial reaction rate 2.7 times higher than the hydrolysis rate with no ionic liquid. The initial yield after 2 h was 0.7 g glucose/g cellulose, and the carrier-free immobilized cellulase (CFIC) was effectively re-used five times.

  4. 16 CFR 501.6 - Cellulose sponges, irregular dimensions.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of...

  5. Characterising the cellulose synthase complexes of cell walls

    NARCIS (Netherlands)

    Mansoori Zangir, N.

    2012-01-01

    One of the characteristics of the plant kingdom is the presence of a structural cell wall. Cellulose is a major component in both the primary and secondary cell walls of plants. In higher plants cellulose is synthesized by so called rosette protein complexes with cellulose synthases (CESAs) as the c

  6. Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets

    Directory of Open Access Journals (Sweden)

    Imjak Jeon

    2011-01-01

    Full Text Available Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less handling difficulty from HPC tackiness as well as easier particle size targeting. Selecting the optimum ratio of plastic excipients and the particle size of starting materials can however be critical issues in this method.

  7. Cellulose acetobutyrate films and beryllium oxide discs for low-level radiation monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Ventura, S.A.; Kleinschmidt, D.E.; Mbu, J.B.

    1976-10-01

    The effect of mylar films on the attenuation of alpha particle energy and the production of etchable tracks in cellulose acetobutyrate was studied. A model developed predicts a 15-..mu.. optimum mylar film thickness, while experimental results indicated a 22.8-..mu.. optimum. The effect of alpha particle and potassium hydroxide solution interaction with CAB was reviewed and process improvements suggested. The TSEE response of BeO discs to tritium at 5.0 mCi/m/sup 3/ for up to 15-hr exposure was also investigated. An average TSEE/..beta.. ratio of 0.02 was obtained.

  8. Isolation of Nanocrystalline Cellulose from oil palm empty fruit bunch – A response surface methodology study

    Directory of Open Access Journals (Sweden)

    Song Yee Kai

    2016-01-01

    Full Text Available The research work studied the extraction of Nano Crystalline Cellulose (NCC from oil palm empty fruit bunch (EFB, with aid of Response Surface Methodology (RSM. Particle size analysis using Malvern Zetasizer had confirmed the extracted NCC fall within the desired nano scaled range. The impact of three input parameters, namely concentration of NaOH solution during alkaline treatment, concentration of H2SO4 solution during acid hydrolysis, and duration for acid hydrolysis on NCC particle were investigated. From ANOVA study, it had suggested that the current RSM model is significant to interpret the interaction among the all three input parameters.

  9. Magnetic Alignment of Cellulose Nanowhiskers in an All-Cellulose Composite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Dongsheng; Liu, Zuyan; Al-Haik, Marwan; Tehrani, Mehran; Murray, Frank; Tennenbaum, Rina; Garmestani, Hamid

    2010-08-01

    Unidirectional reinforced nanocomposite paper was fabricated from cellulose nanowhiskers and wood pulp under an externally-applied magnetic field. A 1.2 Tesla magnetic field was applied in order to align the nanowhiskers in the pulp as it was being formed into a sheet of paper. The magnetic alignment was driven by the characteristic negative diamagnetic anisotropy of the cellulose nanowhiskers. ESEM micrographs demonstrated unidirectional alignment of the nanowhiskers in the all-cellulose composite paper. Comparing with control paper sheets made from wood pulp only, the storage modulus in the all-cellulose nanocomposites increased dramatically. The storage modulus along the direction perpendicular to the magnetic field was much stronger than that parallel to the magnetic field. This new nanocomposite, which contains preferentially-oriented microstructures and has improved mechanical properties, demonstrates the possibility of expanding the functionality of paper products and constitutes a promising alternative to hydrocarbon based materials and fibers.

  10. Segal crystallinity index revisited by the simulation of x-ray diffraction patterns of cotton cellulose IB and cellulose II

    Science.gov (United States)

    The Segal method estimates the amorphous fraction of cellulose IB materials simply based on intensity at 18o 20 in an X-ray diffraction pattern and was extended to cellulose II using 16o 2O intensity. To address the dependency of Segal amorphous intensity on crystal size, cellulose polymorph, and th...

  11. Plackett-Burman experimental design for bacterial cellulose-silica composites synthesis.

    Science.gov (United States)

    Guzun, Anicuta Stoica; Stroescu, Marta; Jinga, Sorin Ion; Voicu, Georgeta; Grumezescu, Alexandru Mihai; Holban, Alina Maria

    2014-09-01

    Bacterial cellulose-silica hybrid composites were prepared starting from wet bacterial cellulose (BC) membranes using Stöber reaction. The structure and surface morphology of hybrid composites were examined by FTIR and SEM. The SEM pictures revealed that the silica particles are attached to BC fibrils and are well dispersed in the BC matrix. The influence of silica particles upon BC crystallinity was studied using XRD analysis. Thermogravimetric (TG) analysis showed that the composites are stable up to 300°C. A Plackett-Burman design was applied in order to investigate the influence of process parameters upon silica particle sizes and silica content of BC-silica composites. The statistical model predicted that it is possible for silica particles size to vary the synthesis parameters in order to obtain silica particles deposed on BC membranes in the range from 34.5 to 500 nm, the significant parameters being ammonia concentration, reaction time and temperature. The silica content also varies depending on process parameters, the statistical model predicting that the most influential parameters are water-tetraethoxysilane (TEOS) ratio and reaction temperature. The antimicrobial behavior on Staphylococcus aureus of BC-silica composites functionalized with usnic acid (UA) was also studied, in order to create improved surfaces with antiadherence and anti-biofilm properties.

  12. Thin blend films of cellulose and polyacrylonitrile

    Science.gov (United States)

    Lu, Rui; Zhang, Xin; Mao, Yimin; Briber, Robert; Wang, Howard

    Cellulose is the most abundant renewable, biocompatible and biodegradable natural polymer. Cellulose exhibits excellent chemical and mechanical stability, which makes it useful for applications such as construction, filtration, bio-scaffolding and packaging. To further expand the potential applications of cellulose materials, their alloying with synthetic polymers has been investigated. In this study, thin films of cotton linter cellulose (CLC) and polyacrylonitrile (PAN) blends with various compositions spanning the entire range from neat CLC to neat PAN were spun cast on silicon wafers from common solutions in dimethyl sulfoxide / ionic liquid mixtures. The morphologies of thin films were characterized using optical microscopy, atomic force microscopy, scanning electron microscopy and X-ray reflectivity. Morphologies of as-cast films are highly sensitive to the film preparation conditions; they vary from featureless smooth films to self-organized ordered nano-patterns to hierarchical structures spanning over multiple length scales from nanometers to tens of microns. By selectively removing the PAN-rich phase, the structures of blend films were studied to gain insights in their very high stability in hot water, acid and salt solutions.

  13. Environmental sustainability of cellulosic energy cropping systems

    Science.gov (United States)

    The environmental sustainability of bioenergy production depends on both direct and indirect effects of the production systems to produce bioenergy feedstocks. This chapter evaluates what is known about the environmental sustainability of cellulosic bioenergy crop production for the types of produc...

  14. Nanomanufacturing metrology for cellulosic nanomaterials: an update

    Science.gov (United States)

    Postek, Michael T.

    2014-08-01

    The development of the metrology and standards for advanced manufacturing of cellulosic nanomaterials (or basically, wood-based nanotechnology) is imperative to the success of this rising economic sector. Wood-based nanotechnology is a revolutionary technology that will create new jobs and strengthen America's forest-based economy through industrial development and expansion. It allows this, previously perceived, low-tech industry to leap-frog directly into high-tech products and processes and thus improves its current economic slump. Recent global investments in nanotechnology programs have led to a deeper appreciation of the high performance nature of cellulose nanomaterials. Cellulose, manufactured to the smallest possible-size ( 2 nm x 100 nm), is a high-value material that enables products to be lighter and stronger; have less embodied energy; utilize no catalysts in the manufacturing, are biologically compatible and, come from a readily renewable resource. In addition to the potential for a dramatic impact on the national economy - estimated to be as much as $250 billion worldwide by 2020 - cellulose-based nanotechnology creates a pathway for expanded and new markets utilizing these renewable materials. The installed capacity associated with the US pulp and paper industry represents an opportunity, with investment, to rapidly move to large scale production of nano-based materials. However, effective imaging, characterization and fundamental measurement science for process control and characterization are lacking at the present time. This talk will discuss some of these needed measurements and potential solutions.

  15. Nanofibrous microfiltration membrane based on cellulose nanowhiskers.

    Science.gov (United States)

    Ma, Hongyang; Burger, Christian; Hsiao, Benjamin S; Chu, Benjamin

    2012-01-09

    A multilayered nanofibrous microfiltration (MF) membrane system with high flux, low pressure drop, and high retention capability against both bacteria and bacteriophages (a virus model) was developed by impregnating ultrafine cellulose nanowhiskers (diameter about 5 nm) into an electrospun polyacrylonitrile (PAN) nanofibrous scaffold (fiber diameter about 150 nm) supported by a poly(ethylene terephthalate) (PET) nonwoven substrate (fiber diameter about 20 μm). The cellulose nanowhiskers were anchored on the PAN nanofiber surface, forming a cross-linked nanostructured mesh with very high surface-to-volume ratio and a negatively charged surface. The mean pore size and pore size distribution of this MF system could be adjusted by the loading of cellulose nanowhiskers, where the resulting membrane not only possessed good mechanical properties but also high surface charge density confirmed by the conductivity titration and zeta potential measurements. The results indicated that a test cellulose nanowhisker-based MF membrane exhibited 16 times higher adsorption capacity against a positively charged dye over a commercial nitrocellulose-based MF membrane. This experimental membrane also showed full retention capability against bacteria, for example, E. coli and B. diminuta (log reduction value (LRV) larger than 6) and decent retention against bacteriophage MS2 (LRV larger than 2).

  16. PRODUCTION AND CHARACTERIZATION OF ECONOMICAL BACTERIAL CELLULOSE

    Directory of Open Access Journals (Sweden)

    Houssni El-Saied

    2008-11-01

    Full Text Available The present study investigates the economical production of bacterial cellulose (BC by Gluconacetobacter subsp. Xylinus (ATCC 10245 in 250 ml Erlenmeyer flasks cultivated under static conditions. The fermentation media used contained food industrial by-product liquors, such as black strap molasses solution and corn steep liquor (CSL, which represents some of the most economical carbon and nitrogen sources. However, because of the presence of undesirable components in molasses (such as coloring substances, heavy metals, and other compounds that may act as inhibitors, and in order to eliminate them, crude molasses has been treated with an acid, as an attempt to increase BC productivity. The amount of BC produced using these carbon and nitrogen sources was determined and compared to that produced using previously reported fermentation media. The characterizations of the bacterial cellulose (BC pellicles obtained using either conventional or by-product media were studied by thermal and spectral techniques and compared to those of plant-derived cellulose such as cotton linter, viscose pulp, and microcrystalline cellulose.

  17. Nitration of Wood Cellulose in HNO3/Organic Solvent Medium

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A steam explosion pretreatment at various severities was applied to pure wood cellulose; the influences of steam pretreatment on the morphological structure, the hydrophilic property and viscosity-average molecular weight of cellulose were evaluated. The nitration of steam-exploded cellulose was carried out in the nitrating agent medium (HNO3/organic solvent). The performance indexes of nitrocellulose, prepared from original and steam exploded samples, were determined by using the polarized optical microscope. The results show that after pretreatment the reactivity of the three hydroxyl groups in anhydroglucose unit of cellulose is improved, and the nitrogen content and the uniformity of NC from steam exploded cellulose observably increas.

  18. Rheology Behavior of Cellulose/NMMO/Water Solution

    Institute of Scientific and Technical Information of China (English)

    顾广新; 胡赛珠; 邵惠丽; 沈弋弋; 胡学超

    2001-01-01

    Rheology properties of cellulose/NMMO/water solution are important parameters for spinning. The storage and loss modulus and viscosity of the solution decrease with increasing water concentration of solvent in certain range. Flow-activation energy of two kinds of cellulose solution is quite different in view of their molecular weight. The molecular weigh distribution of cellulose samples can be characterized by the value of Gc/c Since the different cellulose samples have different MWD and DP, the relations of the first normal stress difference N1 vs. shear rate are different. Moreover, the rheology properties of cellulose solution produced by twin-screw extruder process are also investigated.

  19. Method of forming an electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2011-11-22

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  20. Characterization of cellulose nanowhiskers; Caracterizacao do nanowhiskers de celulose

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Nayra R.; Pinheiro, Ivanei F.; Morales, Ana R.; Ravagnani, Sergio P.; Mei, Lucia, E-mail: 25nareis@gmail.com [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2013-07-01

    Cellulose is the most abundant polymer earth. The cellulose nanowhiskers can be extracted from the cellulose. These have attracted attention for its use in nanostructured materials for various applications, such as nanocomposites, because they have peculiar characteristics, among them, high aspect ratio, biodegradability and excellent mechanical properties. This work aims to characterize cellulose nanowhiskers from microcrystalline cellulose. Therefore, these materials were characterized by X-ray diffraction (XRD) to assess the degree of crystallinity, infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) to the morphology of nanowhiskers and thermal stability was evaluated by Thermogravimetric Analysis (TGA). (author)

  1. Essays concerning the cellulosic biofuel industry

    Science.gov (United States)

    Rosburg, Alicia Sue

    Despite market-based incentives and mandated production, the U.S. cellulosic biofuel industry has been slow to develop. This dissertation explores the economic factors that have limited industry development along with important economic tradeoffs that will be encountered with commercial-scale production. The first essay provides an overview of the policies, potential, and challenges of the biofuel industry, with a focus on cellulosic biofuel. The second essay considers the economics of cellulosic biofuel production. Breakeven models of the local feedstock supply system and biofuel refining process are constructed to develop the Biofuel Breakeven (BioBreak) program, a stochastic, Excel-based program that evaluates the feasibility of local biofuel and biomass markets under various policy and market scenarios. An application of the BioBreak program is presented using expected market conditions for 14 local cellulosic biofuel markets that vary by feedstock and location. The economic costs of biofuel production identified from the BioBreak application are higher than frequently anticipated and raise questions about the potential of cellulosic ethanol as a sustainable and economical substitute for conventional fuels. Program results also are extended using life-cycle analysis to evaluate the cost of reducing GHG emissions by substituting cellulosic ethanol for conventional fuel. The third essay takes a closer look at the economic trade-offs within the biorefinery industry and feedstock production processes. A long-run biomass production through bioenergy conversion cost model is developed that incorporates heterogeneity of biomass suppliers within and between local markets. The model builds on previous literature by treating biomass as a non-commoditized feedstock and relaxes the common assumption of fixed biomass density and price within local markets. An empirical application is provided for switchgrass-based ethanol production within U.S. crop reporting districts

  2. Nano-cellulose derived bioplastic biomaterial data for vehicle bio-bumper from banana peel waste biomass

    Directory of Open Access Journals (Sweden)

    A.B.M. Sharif Hossain

    2016-09-01

    Full Text Available The innovative study was carried out to produce nano-cellulose based bioplastic biomaterials for vehicle use coming after bioprocess technology. The data show that nano-cellulose particle size was 20 nm and negligible water absorption was 0.03% in the bioplastic. Moreover, burning test, size and shape characterizations, spray coating dye, energy test and firmness of bioplastic have been explored and compared with the standardization of synthetic vehicle plastic bumper following the American Society for Testing and Materials (ASTM. Tensile test was observed 120 MPa/kg m3. In addition to that pH and cellulose content were found positive in the bioplastic compared to the synthetic plastic. Chemical tests like K, CO3, Cl2, Na were determined and shown positive results compared to the synthetic plastic using the EN-14214 (European Norm standardization.

  3. Nano-cellulose derived bioplastic biomaterial data for vehicle bio-bumper from banana peel waste biomass.

    Science.gov (United States)

    Sharif Hossain, A B M; Ibrahim, Nasir A; AlEissa, Mohammed Saad

    2016-09-01

    The innovative study was carried out to produce nano-cellulose based bioplastic biomaterials for vehicle use coming after bioprocess technology. The data show that nano-cellulose particle size was 20 nm and negligible water absorption was 0.03% in the bioplastic. Moreover, burning test, size and shape characterizations, spray coating dye, energy test and firmness of bioplastic have been explored and compared with the standardization of synthetic vehicle plastic bumper following the American Society for Testing and Materials (ASTM). Tensile test was observed 120 MPa/kg m(3). In addition to that pH and cellulose content were found positive in the bioplastic compared to the synthetic plastic. Chemical tests like K, CO3, Cl2, Na were determined and shown positive results compared to the synthetic plastic using the EN-14214 (European Norm) standardization.

  4. Pretreatment assisted synthesis and characterization of cellulose nanocrystals and cellulose nanofibers from absorbent cotton.

    Science.gov (United States)

    Abu-Danso, Emmanuel; Srivastava, Varsha; Sillanpää, Mika; Bhatnagar, Amit

    2017-03-30

    In this work, cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) were synthesized from absorbent cotton. Two pretreatments viz. dewaxing and bleaching with mild alkali were applied to the precursor (cotton). Acid hydrolysis was conducted with H2SO4 and dissolution of cotton was achieved with a mixture of NaOH-thiourea-urea-H2O at -3°C. Synthesized cellulose samples were characterized using FTIR, XRD, SEM, BET, and zeta potential. It seems that synthesis conditions contributed to negative surface charge on cellulose samples and CNCs had the higher negative surface charge compared to CNFs. Furthermore, BET surface area, pore volume and pore diameter of CNCs were found to be higher as compared to CNFs. The dewaxed cellulose nanofibers (CNF D) had a slightly higher BET surface area (0.47m(2)/g) and bigger pore diameter (59.87Å) from attenuated contraction compared to waxed cellulose nanofibers (CNFW) (0.38m(2)/g and 44.89Å). The XRD of CNCs revealed a semi-crystalline structure and the dissolution agents influenced the crystallinity of CNFs. SEM images showed the porous nature of CNFs, the flaky nature and the nano-sized width of CNCs. Synthesized CNF D showed a better potential as an adsorbent with an average lead removal efficiency of 91.49% from aqueous solution.

  5. Cellulose affinity purification of fusion proteins tagged with fungal family 1 cellulose-binding domain.

    Science.gov (United States)

    Sugimoto, Naohisa; Igarashi, Kiyohiko; Samejima, Masahiro

    2012-04-01

    N- or C-terminal fusions of red-fluorescent protein (RFP) with various fungal cellulose-binding domains (CBDs) belonging to carbohydrate binding module (CBM) family 1 were expressed in a Pichia pastoris expression system, and the resulting fusion proteins were used to examine the feasibility of large-scale affinity purification of CBD-tagged proteins on cellulose columns. We found that RFP fused with CBD from Trichoderma reesei CBHI (CBD(Tr)(CBHI)) was expressed at up to 1.2g/l in the culture filtrate, which could be directly injected into the cellulose column. The fusion protein was tightly adsorbed on the cellulose column in the presence of a sufficient amount of ammonium sulfate and was efficiently eluted with pure water. Bovine serum albumin (BSA) was not captured under these conditions, whereas both BSA and the fusion protein were adsorbed on a phenyl column, indicating that the cellulose column can be used for the purification of not only hydrophilic proteins but also for hydrophobic proteins. Recovery of various fusion proteins exceeded 80%. Our results indicate that protein purification by expression of a target protein as a fusion with a fungal family 1 CBD tag in a yeast expression system, followed by affinity purification on a cellulose column, is simple, effective and easily scalable.

  6. Investigations for the production of a fermentable feedstock from bagasse using the Purdue cellulose hydrolysis (solvent) system

    Energy Technology Data Exchange (ETDEWEB)

    1983-06-01

    The major objective is to isolate the cellulosic bundles imbedded in the lignin, and thereafter hydrolyze the isolated cellulosic bundles of alpha and hemi-celluloses into sugars of mono-hexose and pentose, respectively, without significant destruction of these sugars. Two approaches for obtaining the stated goals may be followed: (1) dissolve the lignin without changing the cellulosic fraction. Separate the dissolved lignin from the fibrous bundles and hydrolyze the residual fiber into mono-sugars; and (2) dissolve the cellulosic fraction without dissolving the lignin. Hydrolyze the dissolved cellulosic fraction without interference of lignin into mono-sugars. Remove the non-hydrolyzed lignin which is insoluble in aqueous acid solutions, and thus separate the lignin fraction from the aqueous solution containing the mono-sugars from hydrolyzing. Research was conducted on approach No. 1 using the hydrotropic solution of sodium benzene sulfonate for dissolving lignin from the matrix. Removal of lignin was carried out with the use of a high-pressure, stainless steel Parr vessel. To accomplish the second task, sulfur trioxide was employed as a catalyst to hydrolyze cellulose into liquid mono-sugars. SO/sub 3/ when introduced into an air stream at ambient temperature will react with fiber particles and coat them at random with a thin layer of formed H/sub 2/SO/sub 4/. Abrading of treated fiber can take place in an extruding screw press. The degree of abrading results in a plasticized end product. Hydrolysis of the abraded fibrous material can take place without further addition of acid catalyst in the presence of steam. 5 figures, 14 tables. (DMC)

  7. The Synthesis of a Novel Cellulose Physical Gel

    Directory of Open Access Journals (Sweden)

    Jiufang Duan

    2014-01-01

    Full Text Available Cellulose possessing β-cyclodextrin (β-CD was used as a host molecule and cellulose possessing ferrocene (Fc as a guest polymer. Infrared spectra, differential scanning calorimetry (DSC, ultraviolet spectroscopy (UV, and contact angle analysis were used to characterise the material structure and the inclusion behaviour. The results showed that the β-CD-cellulose and the Fc-cellulose can form inclusion complexes. Moreover, ferrocene oxidation, and reduction of state can be adjusted by sodium hypochlorite (NaClO as an oxidant and glutathione (GSH as a reductant. In this study, a physical gel based on β-CD-cellulose/Fc-cellulose was formed under mild conditions in which autonomous healing between cut surfaces occurred after 24 hours. The physical gel can be controlled in the sol-gel transition. The compressive strength of the Fc-cellulose/β-CD-cellulose gel increased with increased cellulose concentration. The host-guest interaction between the side chains of cellulose could strengthen the gel. The cellulose physical gel may eventually be used as a stimulus-responsive, healing material in biomedical applications.

  8. Assessing nano cellulose developments using science and technology indicators

    Energy Technology Data Exchange (ETDEWEB)

    Milanez, Douglas Henrique; Amaral, Roniberto Morato do; Faria, Leandro Innocentini Lopes de; Gregolin, Jose Angelo Rodrigues, E-mail: douglasmilanez@yahoo.com.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Nucleo de Informacao Tecnologica em Materiais. Dept. de Engenharia de Materiais

    2013-11-01

    This research aims to examine scientific and technological trends of developments in nano cellulose based on scientometric and patent indicators obtained from the Science Citation Index and Derwent Innovations Index in 2001-2010. The overall nano cellulose activity indicators were compared to nanotechnology and other selected nano materials. Scientific and technological future developments in nano cellulose were forecasted using extrapolation growth curves and the main countries were also mapped. The results showed that nano cellulose publications and patent documents have increased rapidly over the last five years with an average growth rate higher than that of nanotechnology and fullerene. The USA, Japan, France, Sweden and Finland all played a significant role in nano cellulose development and the extrapolation growth curves suggested that nano cellulose scientific and technological activities are still emerging. Finally, the evidence from this study recommends monitoring nano cellulose S and T advances in the coming years. (author)

  9. Lytic polysaccharide monooxygenases disrupt the cellulose fibers structure

    Science.gov (United States)

    Villares, Ana; Moreau, Céline; Bennati-Granier, Chloé; Garajova, Sona; Foucat, Loïc; Falourd, Xavier; Saake, Bodo; Berrin, Jean-Guy; Cathala, Bernard

    2017-01-01

    Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that breakdown recalcitrant polysaccharides such as cellulose. Here we investigate the action of LPMOs on cellulose fibers. After enzymatic treatment and dispersion, LPMO-treated fibers show intense fibrillation. Cellulose structure modifications visualized at different scales indicate that LPMO creates nicking points that trigger the disintegration of the cellulose fibrillar structure with rupture of chains and release of elementary nanofibrils. Investigation of LPMO action using solid-state NMR provides direct evidence of modification of accessible and inaccessible surfaces surrounding the crystalline core of the fibrils. The chains breakage likely induces modifications of the cellulose network and weakens fibers cohesion promoting their disruption. Besides the formation of new initiation sites for conventional cellulases, this work provides the first evidence of the direct oxidative action of LPMOs with the mechanical weakening of the cellulose ultrastructure. LPMOs can be viewed as promising biocatalysts for enzymatic modification or degradation of cellulose fibers. PMID:28071716

  10. Nanofibers of cellulose and its derivatives fabricated using direct electrospinning.

    Science.gov (United States)

    Ohkawa, Kousaku

    2015-05-19

    A short review with 49 references describes the electrospinninng (ES) process for polysaccharides, cellulose and chitosan, and their derivatives, including cellulose acetate and hydroxypropyl cellulose. A majority of applied studies adopted a two step-process, in which the cellulose acetate was used for the first ES process, followed by acetyl group removal to regenerate cellulose thin fibers. The electrospun nonwoven fabrics (ESNW) of regenerated cellulose can be modified by introduction of aldehyde groups by oxidative cleavage of vicinal diols using periodates, and these aldehyde groups serve as acceptors of foreign substances, with various chemical/biological functions, to be immobilized on the fiber surfaces in the ESNW matrices. Direct electrospinning of cellulose from trifluroacetic acid solution was also developed and the applied studies were summarized to conclude the current trends of interests in the ES and related technologies.

  11. Mechanism of cellobiose inhibition in cellulose hydrolysis by cellobiohydrolase

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yue; WU Bin; YAN Baixu; GAO Peiji

    2004-01-01

    An experimental study of cellobiose inhibition in cellulose hydrolysis by synergism of cellobiohydrolyse I and endoglucanase I is presented. Cellobiose is the structural unit of cellulose molecules and also the main product in enzymatic hydrolysis of cellulose. It has been identified that cellobiose can strongly inhibit hydrolysis reaction of cellulase, whereas it has no effect on the adsorption of cellulase on cellulose surface. The experimental data of FT-IR spectra, fluorescence spectrum and circular dichroism suggested that cellobiose can be combined with tryptophan residue located near the active site of cellobiohydrolase and then form steric hindrance, which prevents cellulose molecule chains from diffusing into active site of cellulase. In addition, the molecular conformation of cellobiohydrolase changes after cellobiose binding, which also causes most of the non-productive adsorption. Under these conditions, microfibrils cannot be separated from cellulose chains, thus further hydrolysis of cellulose can hardly proceed.

  12. Nanofibers of Cellulose and Its Derivatives Fabricated Using Direct Electrospinning

    Directory of Open Access Journals (Sweden)

    Kousaku Ohkawa

    2015-05-01

    Full Text Available A short review with 49 references describes the electrospinninng (ES process for polysaccharides, cellulose and chitosan, and their derivatives, including cellulose acetate and hydroxypropyl cellulose. A majority of applied studies adopted a two step-process, in which the cellulose acetate was used for the first ES process, followed by acetyl group removal to regenerate cellulose thin fibers. The electrospun nonwoven fabrics (ESNW of regenerated cellulose can be modified by introduction of aldehyde groups by oxidative cleavage of vicinal diols using periodates, and these aldehyde groups serve as acceptors of foreign substances, with various chemical/biological functions, to be immobilized on the fiber surfaces in the ESNW matrices. Direct electrospinning of cellulose from trifluroacetic acid solution was also developed and the applied studies were summarized to conclude the current trends of interests in the ES and related technologies.

  13. Characterization of cellulose and other exopolysaccharides produced from Gluconacetobacter strains.

    Science.gov (United States)

    Fang, Lin; Catchmark, Jeffrey M

    2015-01-22

    This study characterized the cellulosic and non-cellulosic exopolysaccharides (EPS) produced by four Gluconacetobacter strains. The yields of bacterial cellulose and water-soluble polysaccharides were dependent on both carbon source and Gluconacetobacter strain. The carbon substrate also affected the composition of the free EPS. When galactose served as an exclusive carbon source, Gluconacetobacter xylinus (G. xylinus) ATCC 53524 and ATCC 700178 produced a distinct alkaline stable crystalline product, which influenced the crystallization of cellulose. Gluconacetobacter hansenii (G. hansenii) ATCC 23769 and ATCC 53582, however, did not exhibit any significant change in cellulose crystal properties when galactose was used as the carbon source. Microscopic observation further confirmed significant incorporation of EPS into the cellulose composites. The cellulosic network produced from galactose medium showed distinctive morphological and structural features compared to that from glucose medium.

  14. Characterization of cellulose extracted from oil palm empty fruit bunch

    Science.gov (United States)

    Sisak, Muhammad Asri Abdul; Daik, Rusli; Ramli, Suria

    2015-09-01

    Recently, cellulose has been studied by many researchers due to its promising properties such as biodegradability, biocompatibility, hydrophilicity and robustness. Due to that it is applied in many fields such as paper, film, drug delivery, membranes, etc. Cellulose can be extracted from various plants while oil palm empty fruit bunch (OPEFB) is the one of its sources. In this study, cellulose was extracted by chemical treatments which involved the use of formic acid and hydrogen peroxide to remove hemicellulose and lignin components. Maximum yield was 43.22%. Based on the FT-IR spectra, the peak of wax (1735 cm-1), hemicellulose (1375 cm-1) and lignin (1248 cm-1 and 1037 cm-1) were not observed in extracted cellulose. TGA analysis showed that the extracted cellulose starts to thermally degrade at 340 °C. The SEM analysis suggested that the cellulose extracted from OPEFB was not much different from commercial cellulose.

  15. On the polymorphic and morphological changes of cellulose nanocrystals (CNC-I) upon mercerization and conversion to CNC-II.

    Science.gov (United States)

    Jin, Ersuo; Guo, Jiaqi; Yang, Fang; Zhu, Yangyang; Song, Junlong; Jin, Yongcan; Rojas, Orlando J

    2016-06-05

    Polymorphic and morphological transformations of cellulosic materials are strongly associated to their properties and applications, especially in the case of emerging nanocelluloses. Related changes that take place upon treatment of cellulose nanocrystals (CNC) in alkaline conditions are studied here by XRD, TEM, AFM, and other techniques. The results indicate polymorphic transformation of CNC proceeds gradually in a certain range of alkali concentrations, i.e. from about 8% to 12.5% NaOH. In such transition alkali concentration, cellulose I and II allomorphs coexists. Such value and range of the transition concentration is strongly interdependent with the crystallite size of CNCs. In addition, it is distinctively lower than that for macroscopic fibers (12-15% NaOH). Transmission electron microscopy and particle sizing reveals that after mercerization CNCs tend to associate. Furthermore, TEMPO-oxidized mercerized CNC reveals the morphology of individual nanocrystal of the cellulose II type, which is composed of some interconnected granular structures. Overall, this work reveals how the polymorphism and morphology of individual CNC change in alkali conditions and sheds light onto the polymorphic transition from cellulose I to II.

  16. Coating of cellulose-TiO2 nanoparticles on cotton fabric for durable photocatalytic self-cleaning and stiffness.

    Science.gov (United States)

    Kale, Bandu Madhukar; Wiener, Jakub; Militky, Jiri; Rwawiire, Samson; Mishra, Rajesh; Jacob, Karl I; Wang, Youjiang

    2016-10-01

    A new route to make cotton fabric self-cleaning and permanently stiff by coating cellulose-TiO2 on its surface is demonstrated herein. Cellulose-TiO2 dispersion was used for coating and was prepared by mixing TiO2 nanoparticles with cellulose in 60% H2SO4 solution. The surface morphology of cellulose-TiO2 nanoparticles coated sample was analyzed by SEM. The appearance of white TiO2 particles on the surface of the cotton fabric confirmed the successful coating process. The Orange II dye was used as stain and its degradation was observed under UV light. X-ray diffraction analysis showed that cellulose II content increases slightly (by 5.3%) after the solvent treatment. Washing fastness study showed that the fabric stiffness was permanent and self-cleaning properties were stable with 1, 3 and 5% TiO2 coated samples. Air and water vapor permeability was not decreased considerably, whereas tensile strength was increased significantly after coating.

  17. Posidonia oceanica as a Renewable Lignocellulosic Biomass for the Synthesis of Cellulose Acetate and Glycidyl Methacrylate Grafted Cellulose

    Directory of Open Access Journals (Sweden)

    Elena Vismara

    2013-05-01

    Full Text Available High-grade cellulose (97% α-cellulose content of 48% crystallinity index was extracted from the renewable marine biomass waste Posidonia oceanica using H2O2 and organic peracids following an environmentally friendly and chlorine-free process. This cellulose appeared as a new high-grade cellulose of waste origin quite similar to the high-grade cellulose extracted from more noble starting materials like wood and cotton linters. The benefits of α-cellulose recovery from P. oceanica were enhanced by its transformation into cellulose acetate CA and cellulose derivative GMA-C. Fully acetylated CA was prepared by conventional acetylation method and easily transformed into a transparent film. GMA-C with a molar substitution (MS of 0.72 was produced by quenching Fenton’s reagent (H2O2/FeSO4 generated cellulose radicals with GMA. GMA grafting endowed high-grade cellulose from Posidonia with adsorption capability. GMA-C removes β-naphthol from water with an efficiency of 47%, as measured by UV-Vis spectroscopy. After hydrolysis of the glycidyl group to glycerol group, the modified GMA-C was able to remove p-nitrophenol from water with an efficiency of 92%, as measured by UV-Vis spectroscopy. α-cellulose and GMA-Cs from Posidonia waste can be considered as new materials of potential industrial and environmental interest.

  18. IMPACTS OF BIOFILM FORMATION ON CELLULOSE FERMENTATION

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    This project addressed four major areas of investigation: i) characterization of formation of Cellulomonas uda biofilms on cellulose; ii) characterization of Clostridium phytofermentans biofilm development; colonization of cellulose and its regulation; iii) characterization of Thermobifida fusca biofilm development; colonization of cellulose and its regulation; and iii) description of the architecture of mature C. uda, C. phytofermentans, and T. fusca biofilms. This research is aimed at advancing understanding of biofilm formation and other complex processes involved in the degradation of the abundant cellulosic biomass, and the biology of the microbes involved. Information obtained from these studies is invaluable in the development of practical applications, such as the single-step bioconversion of cellulose-containing residues to fuels and other bioproducts. Our results have clearly shown that cellulose-decomposing microbes rapidly colonize cellulose and form complex structures typical of biofilms. Furthermore, our observations suggest that, as cells multiply on nutritive surfaces during biofilms formation, dramatic cell morphological changes occur. We speculated that morphological changes, which involve a transition from rod-shaped cells to more rounded forms, might be more apparent in a filamentous microbe. In order to test this hypothesis, we included in our research a study of biofilm formation by T. fusca, a thermophilic cellulolytic actinomycete commonly found in compost. The cellulase system of T. fusca has been extensively detailed through the work of David Wilson and colleagues at Cornell, and also, genome sequence of a T. fusca strain has been determine by the DOE Joint Genome Institute. Thus, T. fusca is an excellent subject for studies of biofilm development and its potential impacts on cellulose degradation. We also completed a study of the chitinase system of C. uda. This work provided essential background information for understanding how C. uda

  19. Preparation and characterization agar-based nanocomposite film reinforced by nanocrystalline cellulose.

    Science.gov (United States)

    Atef, Maryam; Rezaei, Masoud; Behrooz, Rabi

    2014-09-01

    Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) with particle size of 24.7 μm using sulfuric acid hydrolysis technique. The obtained NCC revealed size of 0-100 nm, which the major part of them was about 30 nm. Then different contents (2.5, 5 and 10 wt%) of these NCC incorporated in agar film solution and the morphology, structure, and properties of the nanocomposite films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), mechanical, physical and optical testing. Results showed that the water vapor permeability (WVP) and water solubility (WS) of the agar-based nanocomposite films significantly (P0.05). In addition, swelling percentage, transparency and light transmission of the films were decreased by incorporating NCC into polymer matrix.

  20. Microfibrillated cellulose as reinforcement for Li-ion battery polymer electrolytes with excellent mechanical stability

    Science.gov (United States)

    Chiappone, A.; Nair, Jijeesh R.; Gerbaldi, C.; Jabbour, L.; Bongiovanni, R.; Zeno, E.; Beneventi, D.; Penazzi, N.

    Methacrylic-based thermo-set gel-polymer electrolyte membranes obtained by a very easy, fast and reliable free radical photo-polymerisation process and reinforced with microfibrillated cellulose particles are here presented. The morphology of the composite electrolytes is investigated by scanning electron microscopy and their thermal behaviour (characteristic temperatures, degradation temperature) are investigated by thermo-gravimetric analysis and differential scanning calorimetry. The composite membranes prepared exhibit excellent mechanical properties, with a Young's modulus as high as about 80 MPa at ambient temperature. High ionic conductivity (approaching 10 -3 S cm -1 at 25 °C) and good overall electrochemical performances are maintained, enlightening that such specific approach would make these hybrid organic, cellulose-based composite polymer electrolyte systems a strong contender in the field of thin and flexible lithium based power sources.

  1. Study of free radicals in gamma irradiated cellulose of cultural heritage materials using Electron Paramagnetic Resonance

    Science.gov (United States)

    Kodama, Yasko; Rodrigues, Orlando, Jr.; Garcia, Rafael Henrique Lazzari; Santos, Paulo de Souza; Vasquez, Pablo A. S.

    2016-07-01

    Main subject of this article was to study room temperature stable radicals in Co-60 gamma irradiated contemporary paper using Electron Paramagnetic Resonance spectrometer (EPR). XRD was used to study the effect of ionizing radiation on the morphology of book paper. SEM images presented regions with cellulose fibers and regions with particles agglomeration on the cellulose fibers. Those agglomerations were rich in calcium, observed by EDS. XRD analysis confirmed presence of calcium carbonate diffraction peaks. The main objective of this study was to propose a method using conventional kinetics chemical reactions for the observed radical formed by ionizing radiation. Therefore, further analyses were made to study the half-life and the kinetics of the free radical created. This method can be suitably applied to study radicals on cultural heritage objects.

  2. RETENTION AID POLYMER INTERACTIONS WITH CELLULOSIC SURFACES AND SUSPENSIONS: A REVIEW

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2009-05-01

    Full Text Available Retention aids can be defined as very-high-mass, water-soluble polymers that are added to cellulosic fiber slurries before the formation of paper in order to improve the efficiency with which fine particles, including cellulosic fines, are retained in the paper product. Optimization of retention aid performance can be a key to achieving efficient and environmentally responsible papermaking objectives. This article reviews various published theories related to retention aid use. Findings related to three main classes of retention aid polymers are considered: cationic acrylamide copolymers (cPAM, anionic acrylamide copolymers (aPAM, and polyethylene oxide (PEO. While many aspects of the interactions of each of these classes of retention aid products can be understood based on colloid chemistry principles, further research is needed in order to more fully bridge the gap between theory and practice.

  3. Electrically conductive nano graphite-filled bacterial cellulose composites.

    Science.gov (United States)

    Erbas Kiziltas, Esra; Kiziltas, Alper; Rhodes, Kevin; Emanetoglu, Nuri W; Blumentritt, Melanie; Gardner, Douglas J

    2016-01-20

    A unique three dimensional (3D) porous structured bacterial cellulose (BC) can act as a supporting material to deposit the nanofillers in order to create advanced BC-based functional nanomaterials for various technological applications. In this study, novel nanocomposites comprised of BC with exfoliated graphite nanoplatelets (xGnP) incorporated into the BC matrix were prepared using a simple particle impregnation strategy to enhance the thermal properties and electrical conductivity of the BC. The flake-shaped xGnP particles were well dispersed and formed a continuous network throughout the BC matrix. The temperature at 10% weight loss, thermal stability and residual ash content of the nanocomposites increased at higher xGnP loadings. The electrical conductivity of the composites increased with increasing xGnP loading (attaining values 0.75 S/cm with the addition of 2 wt.% of xGnP). The enhanced conductive and thermal properties of the BC-xGnP nanocomposites will broaden applications (biosensors, tissue engineering, etc.) of BC and xGnP.

  4. Evaluation of Microflow Digital Imaging Particle Analysis for Sub-Visible Particles Formulated with an Opaque Vaccine Adjuvant.

    Science.gov (United States)

    Frahm, Grant E; Pochopsky, Alex W T; Clarke, Tessa M; Johnston, Michael J W

    2016-01-01

    Microflow digital imaging (MDI) has become a widely accepted method for assessing sub-visible particles in pharmaceutical formulations however, to date; no data have been presented on the utility of this methodology when formulations include opaque vaccine adjuvants. This study evaluates the ability of MDI to assess sub-visible particles under these conditions. A Fluid Imaging Technologies Inc. FlowCAM® instrument was used to assess a number of sub-visible particle types in solution with increasing concentrations of AddaVax™, a nanoscale squalene-based adjuvant. With the objective (10X) used and the limitations of the sensor resolution, the instrument was incapable of distinguishing between sub-visible particles and AddaVax™ droplets at particle sizes less than 5 μm. The instrument was capable of imaging all particle types assessed (polystyrene beads, borosilicate glass, cellulose, polyethylene protein aggregate mimics, and lysozyme protein aggregates) at sizes greater than 5 μm in concentrations of AddaVax™ up to 50% (vol:vol). Reduced edge gradients and a decrease in measured particle sizes were noted as adjuvant concentrations increased. No significant changes in particle counts were observed for polystyrene particle standards and lysozyme protein aggregates, however significant reductions in particle counts were observed for borosilicate (80% of original) and cellulose (92% of original) particles. This reduction in particle counts may be due to the opaque adjuvant masking translucent particles present in borosilicate and cellulose samples. Although the results suggest that the utility of MDI for assessing sub-visible particles in high concentrations of adjuvant may be highly dependent on particle morphology, we believe that further investigation of this methodology to assess sub-visible particles in challenging formulations is warranted.

  5. Evaluation of Microflow Digital Imaging Particle Analysis for Sub-Visible Particles Formulated with an Opaque Vaccine Adjuvant.

    Directory of Open Access Journals (Sweden)

    Grant E Frahm

    Full Text Available Microflow digital imaging (MDI has become a widely accepted method for assessing sub-visible particles in pharmaceutical formulations however, to date; no data have been presented on the utility of this methodology when formulations include opaque vaccine adjuvants. This study evaluates the ability of MDI to assess sub-visible particles under these conditions. A Fluid Imaging Technologies Inc. FlowCAM® instrument was used to assess a number of sub-visible particle types in solution with increasing concentrations of AddaVax™, a nanoscale squalene-based adjuvant. With the objective (10X used and the limitations of the sensor resolution, the instrument was incapable of distinguishing between sub-visible particles and AddaVax™ droplets at particle sizes less than 5 μm. The instrument was capable of imaging all particle types assessed (polystyrene beads, borosilicate glass, cellulose, polyethylene protein aggregate mimics, and lysozyme protein aggregates at sizes greater than 5 μm in concentrations of AddaVax™ up to 50% (vol:vol. Reduced edge gradients and a decrease in measured particle sizes were noted as adjuvant concentrations increased. No significant changes in particle counts were observed for polystyrene particle standards and lysozyme protein aggregates, however significant reductions in particle counts were observed for borosilicate (80% of original and cellulose (92% of original particles. This reduction in particle counts may be due to the opaque adjuvant masking translucent particles present in borosilicate and cellulose samples. Although the results suggest that the utility of MDI for assessing sub-visible particles in high concentrations of adjuvant may be highly dependent on particle morphology, we believe that further investigation of this methodology to assess sub-visible particles in challenging formulations is warranted.

  6. Pt nanocatalysts supported on reduced graphene oxide for selective conversion of cellulose or cellobiose to sorbitol.

    Science.gov (United States)

    Wang, Ding; Niu, Wenqi; Tan, Minghui; Wu, Mingbo; Zheng, Xuejun; Li, Yanpeng; Tsubaki, Noritatsu

    2014-05-01

    Pt nanocatalysts loaded on reduced graphene oxide (Pt/RGO) were prepared by means of a convenient microwave-assisted reduction approach with ethylene glycol as reductant. The conversion of cellulose or cellobiose into sorbitol was used as an application reaction to investigate their catalytic performance. Various metal nanocatalysts loaded on RGO were compared and RGO-supported Pt exhibited the highest catalytic activity with 91.5 % of sorbitol yield from cellobiose. The catalytic performances of Pt nanocatalysts supported on different carbon materials or on silica support were also compared. The results showed that RGO was the best catalyst support, and the yield of sorbitol was as high as 91.5 % from cellobiose and 58.9 % from cellulose, respectively. The improvement of catalytic activity was attributed to the appropriate Pt particle size and hydrogen spillover effect of Pt/RGO catalyst. Interestingly, the size and dispersion of supported Pt particles could be easily regulated by convenient adjustment of the microwave heating temperature. The catalytic performance was found to initially increase and then decrease with increasing particle size. The optimum Pt particle size was 3.6 nm. These findings may offer useful guidelines for designing novel catalysts with beneficial catalytic performance for biomass conversion.

  7. Cotton cellulose: enzyme adsorption and enzymic hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Beltrame, P.L.; Carniti, P.; Focher, B.; Marzetti, A.; Cattaneo, M.

    1982-01-01

    The adsorption of a crude cellulase complex from Trichoderma viride on variously pretreated cotton cellulose samples was studied in the framework of the Langmuir approach at 2-8 degrees. The saturation amount of adsorbed enzyme was related to the susceptibility of the substrates to hydrolysis. In every case the adsorption process was faster by 2-3 orders of magnitude than the hydrolysis step to give end products. For ZnCl/sub 2/-treated cotton cellulose the Langmuir parameters correlated fairly well with the value of the Michaelis constant, measured for its enzymic hydrolysis, and the adsorptive complex was indistinguishable from the complex of the Michaelis-Menten model for the hydrolysis.

  8. Retention of Cationic Starch onto Cellulose Fibres

    Science.gov (United States)

    Missaoui, Mohamed; Mauret, Evelyne; Belgacem, Mohamed Naceur

    2008-08-01

    Three methods of cationic starch titration were used to quantify its retention on cellulose fibres, namely: (i) the complexation of CS with iodine and measurement of the absorbency of the ensuing blue solution by UV-vis spectroscopy; (ii) hydrolysis of the starch macromolecules followed by the conversion of the resulting sugars to furan-based molecules and quantifying the ensuing mixture by measuring their absorbance at a Ι of 490 nm, using the same technique as previous one and; finally (iii) hydrolysis of starch macromolecules by trifluoro-acetic acid and quantification of the sugars in the resulting hydrolysates by high performance liquid chromatography. The three methods were found to give similar results within the range of CS addition from 0 to 50 mg per g of cellulose fibres.

  9. Cutinase promotes dry esterification of cotton cellulose.

    Science.gov (United States)

    Xiaoman, Zhao; Teresa, Matama; Artur, Ribeiro; Carla, Silva; Jing, Wu; Jiajia, Fu; Artur, Cavaco-Paulo

    2016-01-01

    Cutinase from Thermobifida fusca was used to esterify the hydroxyl groups of cellulose with the fatty acids from triolein. Cutinase and triolein were pre-adsorbed on cotton and the reaction proceeded in a dry state during 48 h at 35°C. The cutinase-catalyzed esterification of the surface of cotton fabric resulted in the linkage of the oleate groups to the glycoside units of cotton cellulose. The superficial modification was confirmed by performing ATR-FTIR on treated cotton samples and by MALDI-TOF analysis of the liquors from the treatment of the esterified cotton with a crude cellulase mixture. Modified cotton fabric also showed a significant increase of hydrophobicity. This work proposes a novel bio-based approach to obtain hydrophobic cotton.

  10. Reinforced plastics and aerogels by nanocrystalline cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Leung, Alfred C. W.; Lam, Edmond; Chong, Jonathan; Hrapovic, Sabahudin; Luong, John H. T., E-mail: john.luong@cnrc-nrc.gc.ca [National Research Council Canada (Canada)

    2013-05-15

    Nanocrystalline cellulose (NCC), a rigid rod-like nanoscale material, can be produced from cellulosic biomass in powder, liquid, or gel forms by acid and chemical hydrolysis. Owing to its unique and exceptional physicochemical properties, the incorporation of a small amount of NCC into plastic enhances the mechanical strength of the latter by several orders of magnitudes. Carbohydrate-based NCC poses no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites and aerogels. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic or hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement effect.

  11. Reinforced plastics and aerogels by nanocrystalline cellulose

    Science.gov (United States)

    Leung, Alfred C. W.; Lam, Edmond; Chong, Jonathan; Hrapovic, Sabahudin; Luong, John H. T.

    2013-05-01

    Nanocrystalline cellulose (NCC), a rigid rod-like nanoscale material, can be produced from cellulosic biomass in powder, liquid, or gel forms by acid and chemical hydrolysis. Owing to its unique and exceptional physicochemical properties, the incorporation of a small amount of NCC into plastic enhances the mechanical strength of the latter by several orders of magnitudes. Carbohydrate-based NCC poses no serious environmental concerns, providing further impetus for the development and applications of this green and renewable biomaterial to fabricate lightweight and biodegradable composites and aerogels. Surface functionalization of NCC remains the main focus of NCC research to tailor its properties for dispersion in hydrophilic or hydrophobic media. It is of uttermost importance to develop tools and protocols for imaging of NCC in a complex matrix and quantify its reinforcement effect.

  12. Unraveling cellulose microfibrils: a twisted tale.

    Science.gov (United States)

    Hadden, Jodi A; French, Alfred D; Woods, Robert J

    2013-10-01

    Molecular dynamics (MD) simulations of cellulose microfibrils are pertinent to the paper, textile, and biofuels industries for their unique capacity to characterize dynamic behavior and atomic-level interactions with solvent molecules and cellulase enzymes. While high-resolution crystallographic data have established a solid basis for computational analysis of cellulose, previous work has demonstrated a tendency for modeled microfibrils to diverge from the linear experimental structure and adopt a twisted conformation. Here, we investigate the dependence of this twisting behavior on computational approximations and establish the theoretical basis for its occurrence. We examine the role of solvent, the effect of nonbonded force field parameters [partial charges and van der Waals (vdW) contributions], and the use of explicitly modeled oxygen lone pairs in both the solute and solvent. Findings suggest that microfibril twisting is favored by vdW interactions, and counteracted by both intrachain hydrogen bonds and solvent effects at the microfibril surface.

  13. A comparative study on properties of micro and nanopapers produced from cellulose and cellulose nanofibres.

    Science.gov (United States)

    Mtibe, A; Linganiso, Linda Z; Mathew, Aji P; Oksman, K; John, Maya J; Anandjiwala, Rajesh D

    2015-03-15

    Cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs) were successfully extracted from cellulose obtained from maize stalk residues. A variety of techniques, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used for characterization and the experimental results showed that lignin and hemicellulose were removed to a greater extent by following the chemical methods. Atomic force microscopy (AFM) results confirmed that the diameters of CNCs and CNFs were ranging from 3 to 7 nm and 4 to 10nm, respectively, with their lengths in micro scale. CNCs suspension showed a flow of birefringence, however, the same was not observed in the case of suspension containing CNFs. XRD analysis confirmed that CNCs had high crystallinity index in comparison to cellulose and CNFs. Nanopapers were prepared from CNCs and CNFs by solvent evaporation method. Micropapers were also prepared from cellulose pulp by the same technique. Nanopapers made from CNFs showed less transparency as compared to nanopapers produced from CNCs whereas high transparency as compared to micropaper. Nanopapers produced from CNFs provided superior mechanical properties as compared to both micropaper and nanopapers produced from CNCs. Also, nanopapers produced from CNFs were thermally more stable as compared to nanopapers produced from CNCs but thermally less stable as compared to micropapers.

  14. Using carboxylated nanocrystalline cellulose as an additive in cellulosic paper and poly (vinyl alcohol) fiber paper.

    Science.gov (United States)

    Cha, Ruitao; Wang, Chengyu; Cheng, Shaoling; He, Zhibin; Jiang, Xingyu

    2014-09-22

    Specialty paper (e.g. cigarette paper and battery diaphragm paper) requires extremely high strength properties. The addition of strength agents plays an important role in increasing strength properties of paper. Nanocrystalline cellulose (NCC), or cellulose whiskers, has the potential to enhance the strength properties of paper via improving inter-fibers bonding. This paper was to determine the potential of using carboxylated nanocrystalline cellulose (CNCC) to improve the strength properties of paper made of cellulosic fiber or poly (vinyl alcohol) (PVA) fiber. The results indicated that the addition of CNCC can effectively improve the strength properties. At a CNCC dosage of 0.7%, the tear index and tensile index of the cellulosic paper reached the maximum of 12.8 mN m2/g and 100.7 Nm/g, respectively. More importantly, when increasing the CNCC dosage from 0.1 to 1.0%, the tear index and tensile index of PVA fiber paper were increased by 67.29%, 22.55%, respectively.

  15. SPECIFIC INTERACTION ACTING AT A CELLULOSE-BINDING DOMAIN/CELLULOSE INTERFACE FOR PAPERMAKING APPLICATION

    Directory of Open Access Journals (Sweden)

    Shingo Yokota

    2008-11-01

    Full Text Available Specific and strong cellulose-binding characteristics were utilized for promoting retention of additives in contaminated papermaking systems. Cellulose-binding domain (CBD of cellulase derived from Trichoderma viride was separated by digestion with papain, and then introduced into anionic polyacrylamide (A-PAM through a condensation reaction using water-soluble carbodiimide. The CBD-modified A-PAM (CBD-A-PAM showed good retention on pulp fibers, resulting in high tensile strength paper sheets. The effect remained almost unchanged in the presence of model interfering substances such as ligninsulfonate and Ca2+ ions, whereas commercial cationic paper-strengthening polymer became ineffective. The cellulose-binding force of CBD was quantitatively determined by atomic force microscopy (AFM in the liquid state. Histidine-tagged CBD protein was obtained using Escherichia coli via an expression of CBD derived from Cellulomonas fimi, and immobilized on a gold-coated AFM probe. A strong attractive force was detected only at a CBD/cellulose interface, even when Ca2+ ions were present in high concentration. Direct estimation of CBD affinity for cellulose substrate by AFM would provide significant information on the interfacial interactions useful for the functional design of papermaking additives.

  16. Structure and properties of a pulp fibre-reinforced composite with regenerated cellulose matrix

    Science.gov (United States)

    Gindl, W.; Schöberl, T.; Keckes, J.

    2006-04-01

    Fully bio-based cellulose cellulose composites were produced by partly dissolving beech pulp fibres in lithium chloride/dimethylacetamide (LiCl/DMAc) and subsequent regeneration of matrix cellulose in the presence of undissolved fibres. Compared to cellulose epoxy composites produced from the same fibres, a two-fold increase in tensile strength and elastic modulus was observed for cellulose cellulose composites. From scanning electron microscopy and nanoindentation it is concluded that changes in the fibre cell wall during LiCl/DMAc treatment, improved matrix properties of regenerated cellulose compared to epoxy, and improved fibre matrix adhesion are responsible for the superior properties of cellulose cellulose composites.

  17. Cellulose - Decomposing Fungi From Saudi Arabian Soils

    OpenAIRE

    Bahkali, Ali H.; Khiyami, Mohammad A.

    1996-01-01

    Thirty fungal species belonging to fifteen genera were collected from 30 soil samples on cellulose Czapek agar. The highest number of fungal species was isolated from Dammam (20 species) followed by Niomas (18 species), Makkah and Riyadh (17 species each), Tabouk (16) species and Jizan (11 species). The most frequent genera isolated were Aspergillus, Pencillium, Alternaria, Ulocladium and Curvularia. Throughout this study, six fungal species belonging to four genera; Ulocladiun septosporum, E...

  18. Digital Color in Cellulose Nanocrystal Films

    OpenAIRE

    Dumanli, Ahu Gümrah; van der Kooij, Hanne M.; Kamita, Gen; Reisner, Erwin; Baumberg, Jeremy J.; Steiner, Ullrich; Vignolini, Silvia

    2014-01-01

    This is the final published version. It first appeared at http://pubs.acs.org/doi/abs/10.1021/am501995e. Cellulose nanocrystals (CNCs) form chiral nematic phases in aqueous suspensions that can be preserved upon evaporation of water. The resulting films show an intense directional coloration determined by their microstructure. Here, microreflection experiments correlated with analysis of the helicoidal nanostructure of the films reveal that the iridescent colors and the ordering of the ind...

  19. Bacterial Cellulose-based Biomimetic Composites

    OpenAIRE

    2010-01-01

    Microbial cellulose has proven to be a remarkably versatile biomaterial and can be used in a wide variety of fields, to produce for instance paper products, electronics, acoustics, and biomedical devices. Various biodegradable and biocompatible polymeric materials have recently been investigated to fabricate inorganic-organic hybrid composites by mimicking the mineralization system of natural bone, with some successful outcomes. However, the search for an ideal biomaterial with properties and...

  20. 21 CFR 177.1400 - Hydroxyethyl cellulose film, water-insoluble.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Hydroxyethyl cellulose film, water-insoluble. 177... cellulose film, water-insoluble. Water-insoluble hydroxyethyl cellulose film may be safely used for... cellulose film consists of a base sheet manufactured by the ethoxylation of cellulose under...

  1. Expression of a mutant form of cellulose synthase AtCesA7 causes dominant negative effect on cellulose biosynthesis.

    Science.gov (United States)

    Zhong, Ruiqin; Morrison, W Herbert; Freshour, Glenn D; Hahn, Michael G; Ye, Zheng-Hua

    2003-06-01

    Cellulose synthase catalytic subunits (CesAs) have been implicated in catalyzing the biosynthesis of cellulose, the major component of plant cell walls. Interactions between CesA subunits are thought to be required for normal cellulose synthesis, which suggests that incorporation of defective CesA subunits into cellulose synthase complex could potentially cause a dominant effect on cellulose synthesis. However, all CesA mutants so far reported have been shown to be recessive in terms of cellulose synthesis. In the course of studying the molecular mechanisms regulating secondary wall formation in fibers, we have found that a mutant allele of AtCesA7 gene in the fra5 (fragile fiber 5) mutant causes a semidominant phenotype in the reduction of fiber cell wall thickness and cellulose content. The fra5 missense mutation occurred in a conserved amino acid located in the second cytoplasmic domain of AtCesA7. Overexpression of the fra5 mutant cDNA in wild-type plants not only reduced secondary wall thickness and cellulose content but also decreased primary wall thickness and cell elongation. In contrast, overexpression of the fra6 mutant form of AtCesA8 did not cause any reduction in cell wall thickness and cellulose content. These results suggest that the fra5 mutant protein may interfere with the function of endogenous wild-type CesA proteins, thus resulting in a dominant negative effect on cellulose biosynthesis.

  2. BIOSYNTHESIS OF BACTERIAL CELLULOSE BY МEDUSOMYCES GISEVII

    Directory of Open Access Journals (Sweden)

    E. K. Gladysheva

    2015-01-01

    Full Text Available Summary: Bacterial cellulose is an organic material that is synthesized by microorganisms extracellularly. Bacterial cellulose can be used in various industries. Especially, bacterial cellulose has found its application basically in medicine. The production of bacterial cellulose is a complicated and long process. The principal criterion for the process to be successful is bacterial cellulose to be obtained in a higher yield. Russia is lacking an operating facility to produce bacterial cellulose; therefore, research in this art is the hottest topic. This paper reports details on the biosynthesis of bacterial cellulose by the Мedusomyces gisevii microbe and investigates the effect of active acidity level on the bacterial cellulose synthesis. It was found that the synthesis of bacterial cellulose by the symbiosis of Мedusomyces gisevii does not require pH to be artificially maintained. The substrate concentration effect on the bacterial cellulose yield was also examined. The bacterial cellulose synthesis was witnessed to be conjugated with the acetic-acid bacterium growth, and conditions corresponding to a maximal bacterial cells number correspond to a maximum microbial cellulose yield. The maximal bacterial cell number was observed when the glucose concentration in the broth was 20 g/l; as the glucose concentration was increased to 55 g/L, the acetic-acid bacterial cell number diminished in inverse proportion to the substrate concentration, which is likely due to the substrate inhibition. A glucose concentration of 15 g/l and lower is not enough, causing a decrease in the cell number, which is directly proportional to a decline in the substrate concentration. The maximum bacterial cellulose yield (8.7-9.0 % was achieved at an initial glucose concentration of 20-25 g/l in the broth. The conditions providing the maximum bacterial cellulose yield gave an enlarged bacterial cellulose specimen 605 g in weight. The physicochemical properties of the

  3. All-cellulose nanocomposite film made from bagasse cellulose nanofibers for food packaging application.

    Science.gov (United States)

    Ghaderi, Moein; Mousavi, Mohammad; Yousefi, Hossein; Labbafi, Mohsen

    2014-04-15

    All-cellulose nanocomposite (ACNC) film was produced from sugarcane bagasse nanofibers using N,N-dimethylacetamide/lithium chloride solvent. The average diameter of bagasse fibers (14 μm) was downsized to 39 nm after disk grinding process. X-ray diffraction showed that apparent crystallinity and crystallite size decreased relatively to an increased duration of dissolution time. Thermogravimetric analysis confirmed that thermal stability of the ACNC was slightly less than that of the pure cellulose nanofiber sheet. Tensile strength of the fiber sheet, nanofiber sheet and ACNC prepared with 10 min dissolution time were 8, 101 and 140 MPa, respectively. Water vapor permeability (WVP) of the ACNC film increased relatively to an increased duration of dissolution time. ACNC can be considered as a multi-performance material with potential for application in cellulose-based food packaging owing to its promising properties (tough, bio-based, biodegradable and acceptable levels of WVP).

  4. Preparation and Characterization of Super Absorbent Resin from Natural Cellulose

    Institute of Scientific and Technical Information of China (English)

    李杰; 马凤国; 谭惠民

    2003-01-01

    The grafting polyacrylamide onto wood pulp cellulose (cell-g-PAM) was performed with cerous ammonium nitrate as the initiator and hydrolyzed to produce the super absorbent resin. The FTIR shows that the polyacrylamide is grafted on the cellulose. After hydrolyzation, part of acrylamino groups are transformed into carboxyl groups. The XRD analysis shows that the graft polymerization occurred at the amorphous section and the surface of the crystal section of cellulose. The SEM graph reveals that there is a layer of polymer on the surface of cellulose fiber and the fibril structure of the cellulose surface is covered. After hydrolyzation, the surface of the product is different from that of cell-g-PAM's and the surface is scraggy. The technical conditions to prepare high water absorbent resin were confirmed. Through the radical graft copolymerization, the high water absorbent resin can be produced from wood pulp cellulose.

  5. Traffic jams reduce hydrolytic efficiency of cellulase on cellulose surface.

    Science.gov (United States)

    Igarashi, Kiyohiko; Uchihashi, Takayuki; Koivula, Anu; Wada, Masahisa; Kimura, Satoshi; Okamoto, Tetsuaki; Penttilä, Merja; Ando, Toshio; Samejima, Masahiro

    2011-09-02

    A deeper mechanistic understanding of the saccharification of cellulosic biomass could enhance the efficiency of biofuels development. We report here the real-time visualization of crystalline cellulose degradation by individual cellulase enzymes through use of an advanced version of high-speed atomic force microscopy. Trichoderma reesei cellobiohydrolase I (TrCel7A) molecules were observed to slide unidirectionally along the crystalline cellulose surface but at one point exhibited collective halting analogous to a traffic jam. Changing the crystalline polymorphic form of cellulose by means of an ammonia treatment increased the apparent number of accessible lanes on the crystalline surface and consequently the number of moving cellulase molecules. Treatment of this bulky crystalline cellulose simultaneously or separately with T. reesei cellobiohydrolase II (TrCel6A) resulted in a remarkable increase in the proportion of mobile enzyme molecules on the surface. Cellulose was completely degraded by the synergistic action between the two enzymes.

  6. Cellulose-Based Bio- and Nanocomposites: A Review

    Directory of Open Access Journals (Sweden)

    Susheel Kalia

    2011-01-01

    Full Text Available Cellulose macro- and nanofibers have gained increasing attention due to the high strength and stiffness, biodegradability and renewability, and their production and application in development of composites. Application of cellulose nanofibers for the development of composites is a relatively new research area. Cellulose macro- and nanofibers can be used as reinforcement in composite materials because of enhanced mechanical, thermal, and biodegradation properties of composites. Cellulose fibers are hydrophilic in nature, so it becomes necessary to increase their surface roughness for the development of composites with enhanced properties. In the present paper, we have reviewed the surface modification of cellulose fibers by various methods. Processing methods, properties, and various applications of nanocellulose and cellulosic composites are also discussed in this paper.

  7. Metallization of bacterial cellulose for electrical and electronic device manufacture

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Jansen, Valerie Malyvanh; Woodward, Jonathan

    2011-06-07

    A method for the deposition of metals in bacterial cellulose and for the employment of the metallized bacterial cellulose in the construction of fuel cells and other electronic devices is disclosed. The method for impregnating bacterial cellulose with a metal comprises placing a bacterial cellulose matrix in a solution of a metal salt such that the metal salt is reduced to metallic form and the metal precipitates in or on the matrix. The method for the construction of a fuel cell comprises placing a hydrated bacterial cellulose support structure in a solution of a metal salt such that the metal precipitates in or on the support structure, inserting contact wires into two pieces of the metal impregnated support structure, placing the two pieces of metal impregnated support structure on opposite sides of a layer of hydrated bacterial cellulose, and dehydrating the three layer structure to create a fuel cell.

  8. Effect of Surface Attachment on Synthesis of Bacterial Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Evans, Barbara R [ORNL; O' Neill, Hugh Michael [ORNL

    2005-01-01

    Gluconacetobacter spp. synthesize a pure form of hydrophilic cellulose that has several industrial specialty applications. Literature reports have concentrated on intensive investigation of static and agitated culture in liquid media containing high nutrient concentrations optimized for maximal cellulose production rates. The behavior of these bacteria on semisolid and solid surfaces has not been specifically addressed. The species Gluconacetobacter hansenii was examined for cellulose synthesis and colony morphology on a range of solid supports, including cotton linters, and on media thickened with agar, methyl cellulose, or gellan. The concentration and chemical structure of the thickening agent were found to be directly related to the formation of contiguous cellulose pellicules. Viability of the bacteria following freezer storage was improved when the bacteria were frozen in their cellulose pellicules.

  9. In situ synthesis of polysaccharide nanoparticles via polyion complex of carboxymethyl cellulose and chitosan.

    Science.gov (United States)

    Kaihara, Sachiko; Suzuki, Yoichi; Fujimoto, Keiji

    2011-07-01

    Biocompatible polymer-magnetite hybrid nanoparticles were prepared by means of in situ synthesis of magnetite within polysaccharide hydrogel nanoparticles. Hydrogel nanoparticles were first fabricated by blending high-molecular-weight carboxymethyl cellulose as an anionic polymer, and low-molecular-weight chitosan as a cationic polymer to form polyion complexes (CC particles). These polyion complexes were then chemically crosslinked using genipin, a bio-based cross-linker, to form stable nanoparticles having a semi-IPN structure (CCG particles). Magnetite was lastly synthesized within CCG particles by the coprecipitation method to obtain polymer-magnetite hybrid nanoparticles (CCGM particles). The formations of CC, CCG and CCGM particles were mainly observed by transmittance, absorbance of genipin and TEM, respectively, and their hydrodynamic diameters and zeta-potentials were analyzed. It was confirmed that the hydrodynamic diameters and the zeta-potentials of these particles were significantly influenced by pH of the suspension, which was attributed to the charges of polymers. The diameters of CCGM particles were smaller than 200 nm at any pH conditions, suggesting the possibility to apply them as drug delivery carriers. CCGM particles exhibited the responsiveness to a magnetic field in addition to their high dispersion stability, indicating their potential to be utilized as a biomaterial for hyperthermia.

  10. USE CELLULOSE FOR CLEANING CONCENTRATED SUGAR SOLUTIONS

    Directory of Open Access Journals (Sweden)

    N. G. Kul’neva

    2015-01-01

    Full Text Available Summary. Producing high quality intermediate products in the boiling-crystallization station is an actual problem of sugar production. In the production of white sugar brown sugar syrup is not further purified that decreases the quality of the end product. Studies have been conducted using cellulose as an adsorbent for the purification of concentrated sugar solutions, having affinity to dyes and other impurities. Research have been carried out with the intermediate products of the Lebedyan sugar plant. Test results have shown cellulose ability to adsorb the dyes in sugar production. The influence of the adsorbent concentration and the mass fraction of solids in the syrup on the decolorization effect has been studied; rational process parameters have been obtained. It has been found that proceeding an additional adsorption purification of brown sugars syrup allows to reduce the solution color, increase the amount and quality of the end product. Adsorbing means, received from production wastes on the basis of organic resources, have many advantages: economical, environmentally friendly for disposal, safe to use, reliable and efficient in use. Conducted research on using cellulose as adsorbent for treatment of concentrated sugar solutions, having an affinity for colouring matter and other impurities. The experiments were carried out on the intermediates Lebedyanskiy sugar factory. The test results showed the ability of cellulose to adsorb coloring matter of sugar production. To evaluate the effect of bleaching depending on the mass fraction of dry substances prepared yellow juice filtration of sugar concentration of 55, 60, 65 % with subsequent adsorption purification of cellulose. The results of the experiment built adsorption isotherm of dyestuffs. The influence of the concentration of the adsorbent and a mass fraction of solids of juice filtration on the efficiency of decolorization obtained by rational parameters of the process. It is

  11. Smart Cellulose Fibers Coated with Carbon Nanotube Networks

    OpenAIRE

    Haisong Qi; Jianwen Liu; Edith Mäder

    2014-01-01

    Smart multi-walled carbon nanotube (MWCNT)-coated cellulose fibers with a unique sensing ability were manufactured by a simple dip coating process. The formation of electrically-conducting MWCNT networks on cellulose mono- and multi-filament fiber surfaces was confirmed by electrical resistance measurements and visualized by scanning electron microscopy. The interaction between MWCNT networks and cellulose fiber was investigated by Raman spectroscopy. The piezoresistivity of these fibers fo...

  12. High pressure HC1 conversion of cellulose to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Antonoplis, Robert Alexander; Blanch, Harvey W.; Wilke, Charles R.

    1981-08-01

    The production of ethanol from glucose by means of fermentation represents a potential long-range alternative to oil for use as a transportation fuel. Today's rising oil prices and the dwindling world supply of oil have made other fuels, such as ethanol, attractive alternatives. It has been shown that automobiles can operate, with minor alterations, on a 10% ethanol-gasoline mixture popularly known as gasohol. Wood has long been known as a potential source of glucose. Glucose may be obtained from wood following acid hydrolysis. In this research, it was found that saturating wood particles with HCl gas under pressure was an effective pretreatment before subjecting the wood to dilute acid hydrolysis. The pretreatment is necessary because of the tight lattice structure of cellulose, which inhibits dilute acid hydrolysis. HCl gas makes the cellulose more susceptible to hydrolysis and the glucose yield is doubled when dilute acid hydrolysis is preceded by HCl saturation at high pressure. The saturation was most effectively performed in a fluidized bed reactor, with pure HCl gas fluidizing equal volumes of ground wood and inert particles. The fluidized bed effectively dissipated the large amount of heat released upon HCl absorption into the wood. Batch reaction times of one hour at 314.7 p.s.i.a. gave glucose yields of 80% and xylose yields of 95% after dilute acid hydrolysis. A non-catalytic gas-solid reaction model, with gas diffusing through the solid limiting the reaction rate, was found to describe the HCl-wood reaction in the fluidized bed. HCl was found to form a stable adduct with the lignin residue in the wood, in a ratio of 3.33 moles per mole of lignin monomer. This resulted in a loss of 0.1453 lb. of HCl per pound of wood. The adduct was broken upon the addition of water. A process design and economic evaluation for a plant to produce 214 tons per day of glucose from air-dried ground Populus tristi gave an estimated glucose cost of 15.14 cents per pound

  13. Regenerators with cellulose as storage material. Regeneratoren mit Cellulose als Speichermaterial

    Energy Technology Data Exchange (ETDEWEB)

    Schenk, J. (Inst. fuer Luft- und Kaeltetechnik, Dresden (Germany))

    1994-02-01

    Regenerators for heat and mass transfer are mostly based on storage materials made of aluminium or glass and ceramic fibres. For about 15 years, experience with storage masses made of cellulose paper has been available. A development carried out at the Institute for Air and Refrigeration Technology in Dresden led to the production of more than 1000 regenerative energy transfer units in the variant of heat exchanger as well as of enthalpy transfer units. At present, an advanced line of products of cellulose storage masses is prepared. The relations to be observed between microgeometry of the storage mass and performance data, such as transmission level and pressure loss, are presented. (orig.)

  14. Synthesis and Characterization of a Novel Cellulose Nonionic Ether

    Institute of Scientific and Technical Information of China (English)

    SHAO Zi-qiang; XU Kun; TIAN Yong-sheng; WANG Fei-jun; WANG Ji-xun

    2005-01-01

    A kind of novel cellulose ether-trihydroxybutyl cellulose (THBC) was synthesized. The process includes the steam explosion treatment of cotton cellulose, alkalization, etherification and purification. Sweep electron microscope (SEM), Fourier transform infrared (FTIR) and X-ray diffraction were used to characterize the cellulose pretreated and the product. The effects of reaction conditions (temperature, time) on the molecular substitution (Sm) were discussed. To obtain a higher degree of molecular substitution, the reaction temperature is 80 ℃, and the reaction time is 4 h.

  15. Synthesis of cellulose dehydroabietate in ionic liquid [bmim]Br.

    Science.gov (United States)

    Xu, Xuetang; Duan, Wengui; Huang, Mei; Li, Guanghua

    2011-09-27

    A new type of cellulose derivative, cellulose dehydroabietate (CDA), was synthesized by the O-acylation reaction of cellulose with dehydroabietic acid chloride (DHAC) using ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) as a solvent and 4-dimethyl-aminopyridine (DMAP) as a catalyst. The resulting CDA was characterized by means of FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and elemental analysis. Also, some properties of CDA were determined. These results showed that CDA has better solubility, water-repellency, and resistance to acids and bases than raw cellulose, and these properties increase with the DS of CDA.

  16. Effects of Ethanol Pulping on the Length of Bamboo Cellulose

    Institute of Scientific and Technical Information of China (English)

    Tao Yang; Liao Junhe; Luo Xuegang

    2006-01-01

    On the conditions of different ethanol concentration, acids and catalyzers, the effects of ethanol pulping on the cellulose length of bamboo were studied. The results indicates that ethanol pulping has remarkable effects on the length of cellulose, which is clearly reduced with adding ethanol and acid. The margin of length of cellulose become smaller with the increase of the catalyzer. When the ethanol concentration was 70%, the concentration of acid was 0.3% and some NaOH was used as catalyzer, the length of cellulose was the longest.

  17. CELLULOSE EXTRACTION FROM PALM KERNEL CAKE USING LIQUID PHASE OXIDATION

    OpenAIRE

    FARM YAN YAN; DUDUKU KRISHNIAH; MARIANI RAJIN; AWANG BONO

    2009-01-01

    Cellulose is widely used in many aspect and industries such as food industry, pharmaceutical, paint, polymers, and many more. Due to the increasing demand in the market, studies and work to produce cellulose are still rapidly developing. In this work, liquid phase oxidation was used to extract cellulose from palm kernel cake to separate hemicellulose, cellulose and lignin. The method is basically a two-step process. Palm kernel cake was pretreated in hot water at 180°C and followed by liquid ...

  18. Spider Silk-CBD-Cellulose Nanocrystal Composites: Mechanism of Assembly

    OpenAIRE

    Sigal Meirovitch; Zvi Shtein; Tal Ben-Shalom; Shaul Lapidot; Carmen Tamburu; Xiao Hu; Kluge, Jonathan A; Uri Raviv; Kaplan, David L.; Oded Shoseyov

    2016-01-01

    The fabrication of cellulose-spider silk bio-nanocomposites comprised of cellulose nanocrystals (CNCs) and recombinant spider silk protein fused to a cellulose binding domain (CBD) is described. Silk-CBD successfully binds cellulose, and unlike recombinant silk alone, silk-CBD self-assembles into microfibrils even in the absence of CNCs. Silk-CBD-CNC composite sponges and films show changes in internal structure and CNC alignment related to the addition of silk-CBD. The silk-CBD sponges exhib...

  19. Characterization of Bacterial Cellulose by Gluconacetobacter hansenii CGMCC 3917.

    Science.gov (United States)

    Feng, Xianchao; Ullah, Niamat; Wang, Xuejiao; Sun, Xuchun; Li, Chenyi; Bai, Yun; Chen, Lin; Li, Zhixi

    2015-10-01

    In this study, comprehensive characterization and drying methods on properties of bacterial cellulose were analyzed. Bacterial cellulose was prepared by Gluconacetobacter hansenii CGMCC 3917, which was mutated by high hydrostatic pressure (HHP) treatment. Bacterial cellulose is mainly comprised of cellulose Iα with high crystallinity and purity. High-water holding and absorption capacity were examined by reticulated structure. Thermogravimetric analysis showed high thermal stability. High tensile strength and Young's modulus indicated its mechanical properties. The rheological analysis showed that bacterial cellulose had good consistency and viscosity. These results indicated that bacterial cellulose is a potential food additive and also could be used for a food packaging material. The high textural stability during freeze-thaw cycles makes bacterial cellulose an effective additive for frozen food products. In addition, the properties of bacterial cellulose can be affected by drying methods. Our results suggest that the bacterial cellulose produced from HHP-mutant strain has an effective characterization, which can be used for a wide range of applications in food industry.

  20. Cellulosic Fibers: Effect of Processing on Fiber Bundle Strength

    DEFF Research Database (Denmark)

    Thygesen, Anders; Madsen, Bo; Thomsen, Anne Belinda;

    2011-01-01

    A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding, and cotto......A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding...

  1. Modeling of Carbohydrate Binding Modules Complexed to Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Nimlos, M. R.; Beckham, G. T.; Bu, L.; Himmel, M. E.; Crowley, M. F.; Bomble, Y. J.

    2012-01-01

    Modeling results are presented for the interaction of two carbohydrate binding modules (CBMs) with cellulose. The family 1 CBM from Trichoderma reesei's Cel7A cellulase was modeled using molecular dynamics to confirm that this protein selectively binds to the hydrophobic (100) surface of cellulose fibrils and to determine the energetics and mechanisms for locating this surface. Modeling was also conducted of binding of the family 4 CBM from the CbhA complex from Clostridium thermocellum. There is a cleft in this protein, which may accommodate a cellulose chain that is detached from crystalline cellulose. This possibility is explored using molecular dynamics.

  2. Studies on cellulose degradation by a Thermoactinimyces Sp

    Energy Technology Data Exchange (ETDEWEB)

    1977-04-01

    Progress in studies on the mechanism of cellulose degradation by Thermoactinomyces is reported. Two pure cellulosic substrates AVICEL and SOLKA FLOC were used in the experiments. A low substituted carboxymethylcellulose (Hercules 4M CMC), cellobiose, and glucose were also used as growth substrates. Results indicate that glucose is not inhibitory to growth up to 1% concetrations, and that cellobiose may not be a good inducer of the cellobiase enzyme activity. Production of biomass and soluble protein was found to be 50% greater on crystalline AVICEL than on the amorphous SOLKA FLOC, even though approximately the same amount and rate of cellulose degradation occurred. A model for cellulose digestion is presented. (JGB)

  3. Engineering control of bacterial cellulose production using a genetic toolkit and a new cellulose-producing strain.

    Science.gov (United States)

    Florea, Michael; Hagemann, Henrik; Santosa, Gabriella; Abbott, James; Micklem, Chris N; Spencer-Milnes, Xenia; de Arroyo Garcia, Laura; Paschou, Despoina; Lazenbatt, Christopher; Kong, Deze; Chughtai, Haroon; Jensen, Kirsten; Freemont, Paul S; Kitney, Richard; Reeve, Benjamin; Ellis, Tom

    2016-06-14

    Bacterial cellulose is a strong and ultrapure form of cellulose produced naturally by several species of the Acetobacteraceae Its high strength, purity, and biocompatibility make it of great interest to materials science; however, precise control of its biosynthesis has remained a challenge for biotechnology. Here we isolate a strain of Komagataeibacter rhaeticus (K. rhaeticus iGEM) that can produce cellulose at high yields, grow in low-nitrogen conditions, and is highly resistant to toxic chemicals. We achieved external control over its bacterial cellulose production through development of a modular genetic toolkit that enables rational reprogramming of the cell. To further its use as an organism for biotechnology, we sequenced its genome and demonstrate genetic circuits that enable functionalization and patterning of heterologous gene expression within the cellulose matrix. This work lays the foundations for using genetic engineering to produce cellulose-based materials, with numerous applications in basic science, materials engineering, and biotechnology.

  4. Steric Stabilization of “Charge-Free” Cellulose Nanowhiskers by Grafting of Poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Jun Araki

    2014-12-01

    Full Text Available A sterically stabilized aqueous suspension of “charge-free” cellulose nanowhiskers was prepared by hydrochloric acid hydrolysis of cotton powders and subsequent surface grafting of monomethoxy poly(ethylene glycol (mPEG. The preparation scheme included carboxylation of the terminal hydroxyl groups in mPEG via oxidation with silica gel particles carrying 2,2,6,6-tetramethyl-1-pyperidinyloxyl (TEMPO moieties and subsequent esterification between terminal carboxyls in mPEG and surface hydroxyl groups of cellulose nanowhiskers, mediated by 1,1'-carbonyldiimidazole (CDI in dimethyl sulfoxide or dimethylacetamide. Some of the prepared PEG-grafted samples showed remarkable flow birefringence and enhanced stability after 24 h, even in 0.1 M NaCl, suggesting successful steric stabilization by efficient mPEG grafting. Actual PEG grafting via ester linkages was confirmed by attenuated total reflectance-Fourier transform infrared spectrometry. In a typical example, the amount of grafted mPEG was estimated as ca. 0.3 g/g cellulose by two measurements, i.e., weight increase after grafting and weight loss after alkali cleavage of ester linkages. Transmission electron microscopy indicated unchanged nanowhisker morphology after mPEG grafting.

  5. Antimicrobial Activity of Silver Ions Released from Zeolites Immobilized on Cellulose Nanofiber Mats.

    Science.gov (United States)

    Rieger, Katrina A; Cho, Hong Je; Yeung, Hiu Fai; Fan, Wei; Schiffman, Jessica D

    2016-02-10

    In this study, we exploit the high silver ion exchange capability of Linde Type A (LTA) zeolites and present, for the first time, electrospun nanofiber mats decorated with in-house synthesized silver (Ag(+)) ion exchanged zeolites that function as molecular delivery vehicles. LTA-Large zeolites with a particle size of 6.0 μm were grown on the surface of the cellulose nanofiber mats, whereas LTA-Small zeolites (0.2 μm) and three-dimensionally ordered mesoporous-imprinted (LTA-Meso) zeolites (0.5 μm) were attached to the surface of the cellulose nanofiber mats postsynthesis. After the three zeolite/nanofiber mat assemblies were ion-exchanged with Ag(+) ions, their ion release profiles and ability to inactivate Escherichia coli (E. coli) K12 were evaluated as a function of time. LTA-Large zeolites immobilized on the nanofiber mats displayed more than an 11 times greater E. coli K12 inactivation than the Ag-LTA-Large zeolites that were not immobilized on the nanofiber mats. This study demonstrates that by decorating nanometer to micrometer scale Ag(+) ion-exchanged zeolites on the surface of high porosity, hydrophilic cellulose nanofiber mats, we can achieve a tunable release of Ag(+) ions that inactivate bacteria faster and are more practical to use in applications over powder zeolites.

  6. Integration of Feedstock Assembly System and Cellulosic Ethanol Conversion Models to Analyze Bioenergy System Performance

    Energy Technology Data Exchange (ETDEWEB)

    Jared M. Abodeely; Douglas S. McCorkle; Kenneth M. Bryden; David J. Muth; Daniel Wendt; Kevin Kenney

    2010-09-01

    Research barriers continue to exist in all phases of the emerging cellulosic ethanol biorefining industry. These barriers include the identification and development of a sustainable and abundant biomass feedstock, the assembly of viable assembly systems formatting the feedstock and moving it from the field (e.g., the forest) to the biorefinery, and improving conversion technologies. Each of these phases of cellulosic ethanol production are fundamentally connected, but computational tools used to support and inform analysis within each phase remain largely disparate. This paper discusses the integration of a feedstock assembly system modeling toolkit and an Aspen Plus® conversion process model. Many important biomass feedstock characteristics, such as composition, moisture, particle size and distribution, ash content, etc. are impacted and most effectively managed within the assembly system, but generally come at an economic cost. This integration of the assembly system and the conversion process modeling tools will facilitate a seamless investigation of the assembly system conversion process interface. Through the integrated framework, the user can design the assembly system for a particular biorefinery by specifying location, feedstock, equipment, and unit operation specifications. The assembly system modeling toolkit then provides economic valuation, and detailed biomass feedstock composition and formatting information. This data is seamlessly and dynamically used to run the Aspen Plus® conversion process model. The model can then be used to investigate the design of systems for cellulosic ethanol production from field to final product.

  7. Synthesis, Antibacterial and Thermal Studies of Cellulose Nanocrystal Stabilized ZnO-Ag Heterostructure Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohd Zobir Hussein

    2013-05-01

    Full Text Available Synthesis of ZnO-Ag heterostructure nanoparticles was carried out by a precipitation method with cellulose nanocrystals (CNCs as a stabilizer for antimicrobial and thermal studies. ZnO-Ag nanoparticles were obtained from various weight percentages of added AgNO3 relative to Zn precursors for evaluating the best composition with enhanced functional properties. The ZnO-Ag/CNCs samples were characterized systematically by TEM, XRD, UV, TGA and DTG. From the TEM studies we observed that ZnO-Ag heterostructure nanoparticles have spherical shapes with size diameters in a 9–35 nm range. The antibacterial activities of samples were assessed against the bacterial species Salmonella choleraesuis and Staphylococcus aureus. The CNC-stabilized ZnO-Ag exhibited greater bactericidal activity compared to cellulose-free ZnO-Ag heterostructure nanoparticles of the same particle size. The incorporation of ZnO-Ag hetreostructure nanoparticles significantly increased the thermal stability of cellulose nanocrystals.

  8. Research into the pyrolysis of pure cellulose, lignin, and birch wood flour in the China Lake entrained-flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Diebold, J.

    1980-06-01

    This experimental program used the China Lake entrained-flow pyrolysis reactor to briefly investigate the pyrolysis of pure cellulose, pure lignin, and birch wood flour. The study determined that the cellulose and wood flour do pyrolyze to produce primarily gaseous products containing significant amounts of ethylene and other useful hydrocarbons. During attempts to pyrolyze powdered lignin, the material melted and bubbled to block the reactor entrance. The pure cellulose and wood flour produced C/sub 2/ + yields of 12% to 14% by weight, which were less than yields from an organic feedstock derived from processed municipal trash. The char yields were 0.1% by weight from cellulose and 1.5% from birch wood flour - one to two orders of magnitude less than were produced from the trash-derived feedstock. In scanning electron microscope photographs, most of the wood flour char had a sintered and agglomerated appearance, although some particles retained the gross cell characteristics of the wood flour. The appearance of the char particles indicated that the material had once been molten and possibly vapor before it formed spheroidal particles about 1 ..mu..m diameter which agglomerated to form larger char particles. The ability to completely melt or vaporize lignocellulosic materials under conditions of high heating rates has now been demonstrated in a continuous flow reactor and promises new techniques for fast pyrolysis. This char was unexpectedly attracted by a magnet, presumably because of iron contamination from the pyrolysis reactor tube wall. The production of water-insoluble tars was negligible compared to the tars produced from trash-derived feedstock. The production of water-soluble organic materials was fairly low and qualitatively appeared to vary inversely with temperature. This study was of a preliminary nature and additional studies are necessary to optimize ethylene production from these feedstocks.

  9. Manganese-containing cellulose nanocomposites: the restrain effect of cellulose treated with NaOH/urea aqueous solutions.

    Science.gov (United States)

    Ma, Ming-Guo; Deng, Fu; Yao, Ke

    2014-10-13

    In this article, the manganese-containing cellulose nanocomposites were obtained using microcrystalline cellulose and Mn(CH3COO)2 · 4H2O in the NaOH/urea aqueous solutions by a efficient microwave-assisted method. The effects of the heating time and Mn(CH3COO)2 · 4H2O concentration on the cellulose nanocomposites were investigated. It was found that the microcrystalline cellulose pretreated with NaOH/urea aqueous solutions played an important role in the phase, shape, and thermal stability of manganese-containing cellulose nanocomposites. Well-crystalline phases of manganese oxides were not observed in the manganese-containing cellulose nanocomposites. Furthermore, well-crystalline phases of manganese oxides were not also observed by thermal treatment of the manganese-containing cellulose nanocomposites at 600 °C for 3h. These results could be attributed to the restrain effect of cellulose treated with NaOH/urea aqueous solutions. It was supposed the possible mechanism during the phase transformation of cellulose nanocomposites.

  10. ECOLOGY SAFE METHOD OF OBTAINING FROM FIR-WOOD THE CELLULOSIC PRODUCT WITH HIGH CONTENT OF ALFA-CELLULOSE

    OpenAIRE

    Владимир Александрович Левданский; Александр Владимирович Левданский; Борис Николаевич Кузнецов

    2014-01-01

    The «green» method of obtaining from fir-wood the cellulosic product with high content of alpha-cellulose was developed. It consists of the stage of wood delignification by hydrogen peroxide in the medium «acetic acid – water – sulfuric acid catalyst» and of the stage of alkaline treatment by NaOH. Preparation conditions were selected which allow to obtain with an acceptable yield (30–31% mas.) the cellulosic product containing 97,3–98,0% mas. of alpha-cellulose.

  11. The correlation between the enzymatic saccharification and the multidimensional structure of cellulose changed by different pretreatments

    OpenAIRE

    Cui, Ting; Li, Jihong; Yan, Zhipei; Yu, Menghui; Li, Shizhong

    2014-01-01

    Background The bioconversion of cellulose into simple sugars or chemicals has attracted extensive attention in recent decades. The crystal allomorphs of cellulose are key factor affecting cellulose saccharification. However, due to the influence of lignin, hemicelluloses, and different characterization methods in the literature, the effect of cellulose allomorphs on cellulose saccharification is still unresolved. Thus, a systematic research on the effect of different cellulose allomorphs on e...

  12. Flexible bacterial cellulose / permalloy nanocomposite xerogel sheets – Size scalable magnetic actuator-cum-electrical conductor

    Directory of Open Access Journals (Sweden)

    V. Thiruvengadam

    2017-03-01

    Full Text Available Permalloy nanoparticles containing bacterial cellulose hydrogel obtained after reduction was compressed into a xerogel flexible sheet by hot pressing at 60 ° C at different pressures. The permalloy nanoparticles with an ordered structure have a bimodal size distribution centered around 25 nm and 190 nm. The smaller nanoparticles are superparamagnetic while the larger particles are ferromagnetic at room temperature. The sheets have a room temperature magnetisation of 20 emug-1 and a coercivity of 32 Oe. The electrical conductivity of the flexible sheets increases with hot pressing pressure from 7 Scm-1 to 40 Scm-1 at room temperature.

  13. Surface hydrophobic modification of cellulose membranes by plasma-assisted deposition of hydrocarbon films

    Directory of Open Access Journals (Sweden)

    Mudtorlep Nisoa

    2010-03-01

    Full Text Available Surface modification by plasma polymerization is an efficient method to change the surface properties of a membrane. Desirable functionality such as hydrophobicity or hydrophilicity can be obtained, depending on plasma chemistry of gas precursors and discharge conditions. In this work, RF magnetron plasma is produced using acetylene and nitrogen as precursor gases. Variations of RF power, particle flux, deposited time and pressure of the precursor gases have been made to observe coating effects on the cellulose membranes. When appropriated conditions are used, a thin brownish film of hydrocarbon was formed on the membrane, and the water contact angle increased from 35 to 130 degrees.

  14. Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water

    Science.gov (United States)

    Olanrewaju, Kazeem Bode

    The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in

  15. Regenerating cellulose from ionic liquids for an accelerated enzymatic hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Hua [Savannah State University; Jones, Cecil L [Savannah State University; Baker, Gary A [ORNL; Xia, Shuqian [Tianjin University, Tianjin, China; Olubajo, Olarongbe [Savannah State University; Person, Vernecia [Savannah State University

    2009-01-01

    The efficient conversion of lignocellulosic materials into fuel ethanol has become a research priority in producing affordable and renewable energy. The pretreatment of lignocelluloses is known to be key to the fast enzymatic hydrolysis of cellulose. Recently, certain ionic liquids (ILs)were found capable of dissolving more than 10 wt% cellulose. Preliminary investigations [Dadi, A.P., Varanasi, S., Schall, C.A., 2006. Enhancement of cellulose saccharification kinetics using an ionic liquid pretreatment step. Biotechnol. Bioeng. 95, 904 910; Liu, L., Chen, H., 2006. Enzymatic hydrolysis of cellulose materials treated with ionic liquid [BMIM]Cl. Chin. Sci. Bull. 51, 2432 2436; Dadi, A.P., Schall, C.A., Varanasi, S., 2007. Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment. Appl. Biochem. Biotechnol. 137 140, 407 421] suggest that celluloses regenerated from IL solutions are subject to faster saccharification than untreated substrates. These encouraging results offer the possibility of using ILs as alternative and nonvolatile solvents for cellulose pretreatment. However, these studies are limited to two chloride-based ILs: (a) 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), which is a corrosive, toxic and extremely hygroscopic solid (m.p. 70 C), and (b) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), which is viscous and has a reactive side-chain. Therefore, more in-depth research involving other ILs is much needed to explore this promising pretreatment route. For this reason, we studied a number of chloride- and acetate-based ILs for cellulose regeneration, including several ILs newly developed in our laboratory. This will enable us to select inexpensive, efficient and environmentally benign solvents for processing cellulosic biomass. Our data confirm that all regenerated celluloses are less crystalline (58 75% lower) and more accessible to cellulase (>2 times) than untreated substrates. As a result, regenerated Avicel

  16. Evaluating Models of Cellulose Degradation by Fibrobacter succinogenes S85.

    Directory of Open Access Journals (Sweden)

    Meagan C Burnet

    Full Text Available Fibrobacter succinogenes S85 is an anaerobic non-cellulosome utilizing cellulolytic bacterium originally isolated from the cow rumen microbial community. Efforts to elucidate its cellulolytic machinery have resulted in the proposal of numerous models which involve cell-surface attachment via a combination of cellulose-binding fibro-slime proteins and pili, the production of cellulolytic vesicles, and the entry of cellulose fibers into the periplasmic space. Here, we used a combination of RNA-sequencing, proteomics, and transmission electron microscopy (TEM to further clarify the cellulolytic mechanism of F. succinogenes. Our RNA-sequence analysis shows that genes encoding type II and III secretion systems, fibro-slime proteins, and pili are differentially expressed on cellulose, relative to glucose. A subcellular fractionation of cells grown on cellulose revealed that carbohydrate active enzymes associated with cellulose deconstruction and fibro-slime proteins were greater in the extracellular medium, as compared to the periplasm and outer membrane fractions. TEMs of samples harvested at mid-exponential and stationary phases of growth on cellulose and glucose showed the presence of grooves in the cellulose between the bacterial cells and substrate, suggesting enzymes work extracellularly for cellulose degradation. Membrane vesicles were only observed in stationary phase cultures grown on cellulose. These results provide evidence that F. succinogenes attaches to cellulose fibers using fibro-slime and pili, produces cellulases, such as endoglucanases, that are secreted extracellularly using type II and III secretion systems, and degrades the cellulose into cellodextrins that are then imported back into the periplasm for further digestion by β-glucanases and other cellulases.

  17. Evaluating Models of Cellulose Degradation by Fibrobacter succinogenes S85.

    Science.gov (United States)

    Burnet, Meagan C; Dohnalkova, Alice C; Neumann, Anthony P; Lipton, Mary S; Smith, Richard D; Suen, Garret; Callister, Stephen J

    2015-01-01

    Fibrobacter succinogenes S85 is an anaerobic non-cellulosome utilizing cellulolytic bacterium originally isolated from the cow rumen microbial community. Efforts to elucidate its cellulolytic machinery have resulted in the proposal of numerous models which involve cell-surface attachment via a combination of cellulose-binding fibro-slime proteins and pili, the production of cellulolytic vesicles, and the entry of cellulose fibers into the periplasmic space. Here, we used a combination of RNA-sequencing, proteomics, and transmission electron microscopy (TEM) to further clarify the cellulolytic mechanism of F. succinogenes. Our RNA-sequence analysis shows that genes encoding type II and III secretion systems, fibro-slime proteins, and pili are differentially expressed on cellulose, relative to glucose. A subcellular fractionation of cells grown on cellulose revealed that carbohydrate active enzymes associated with cellulose deconstruction and fibro-slime proteins were greater in the extracellular medium, as compared to the periplasm and outer membrane fractions. TEMs of samples harvested at mid-exponential and stationary phases of growth on cellulose and glucose showed the presence of grooves in the cellulose between the bacterial cells and substrate, suggesting enzymes work extracellularly for cellulose degradation. Membrane vesicles were only observed in stationary phase cultures grown on cellulose. These results provide evidence that F. succinogenes attaches to cellulose fibers using fibro-slime and pili, produces cellulases, such as endoglucanases, that are secreted extracellularly using type II and III secretion systems, and degrades the cellulose into cellodextrins that are then imported back into the periplasm for further digestion by β-glucanases and other cellulases.

  18. Uniaxially aligned electrospun all-cellulose nanocomposite nanofibers reinforced with cellulose nanocrystals: scaffold for tissue engineering.

    Science.gov (United States)

    He, Xu; Xiao, Qiang; Lu, Canhui; Wang, Yaru; Zhang, Xiaofang; Zhao, Jiangqi; Zhang, Wei; Zhang, Ximu; Deng, Yulin

    2014-02-10

    Uniaxially aligned cellulose nanofibers with well oriented cellulose nanocrystals (CNCs) embedded were fabricated via electrospinning using a rotating drum as the collector. Scanning electron microscope (SEM) images indicated that most cellulose nanofibers were uniaxially aligned. The incorporation of CNCs into the spinning dope resulted in more uniform morphology of the electrospun cellulose/CNCs nanocomposite nanofibers (ECCNN). Polarized light microscope (PLM) and transmission electron microscope (TEM) showed that CNCs dispersed well in ECCNN nonwovens and achieved considerable orientation along the long axis direction. This unique hierarchical microstructure of ECCNN nonwovens gave rise to remarkable enhancement of their physical properties. By incorporating 20% loading (in weight) of CNCs, the tensile strength and elastic modulus of ECCNN along the fiber alignment direction were increased by 101.7 and 171.6%, respectively. Their thermal stability was significantly improved as well. In addition, the ECCNN nonwovens were assessed as potential scaffold materials for tissue engineering. It was elucidated from MTT tests that the ECCNN were essentially nontoxic to human cells. Cell culture experiments demonstrated that cells could proliferate rapidly not only on the surface but also deep inside the ECCNN. More importantly, the aligned nanofibers of ECCNN exhibited a strong effect on directing cellular organization. This feature made the scaffold particularly useful for various artificial tissues or organs, such as blood vessel, tendon, nerve, and so on, in which cell orientation was crucial for their performance.

  19. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles

    Science.gov (United States)

    It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th...

  20. Chemical modification of cellulose extracted from sugarcane bagasse: Preparation of hydroxyethyl cellulose

    Directory of Open Access Journals (Sweden)

    E.S. Abdel-Halim

    2014-07-01

    Full Text Available Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1 N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95 °C using 5 g/l sodium chlorite together with 0.02 g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose, carrying out the reaction at 100 °C for 60 min.

  1. Mineralization of cellulose in frozen boreal soils

    Science.gov (United States)

    Oquist, Mats G.; Segura, Javier; Sparrman, Tobias; Nilsson, Mats; Schleucher, Jurgen

    2015-04-01

    Soils of high-latitude ecosystems store a large fraction of the global soil carbon. In boreal forests, the microbial mineralization of soil organic matter (SOM) during winter can affect the ecosystems net carbon balance. Recent research has shown that microorganisms in the organic surface layer of boreal forest soil can mineralize and grow on simple, soluble monomeric substrates under frozen conditions. However, any substantial impacts of microbial activity in frozen soils on long-term soil carbon balances ultimately depends on whether soil microorganisms can utilize and grow the more complex, polymeric constituents of SOM. In order to evaluate the potential for soil microorganisms to metabolize carbon polymers at low temperatures, we incubated boreal forest soil samples amended with [13C]-cellulose and studied the microbial catabolic and anabolic utilization of the substrate under frozen and unfrozen conditions (-4 and +4°C). Freezing of the soil markedly reduced microbial utilization of the cellulose. The [13C]-CO2 production rate in the samples at +4°C were 0.52 mg CO2 SOM -1 day-1 while rates in the frozen samples (-4°C) were 0.01 mg CO2 SOM -1 day-1. However, newly synthetized [13C]-enriched cell membrane lipids, PLFAs, were detected in soil samples incubated both above and below freezing, confirming that cellulose can sustain also anabolic activity of the microbial populations under frozen conditions. The reduced metabolic rates induced by freezing indicate constraints on exoenzymatic activity, as well as substrate diffusion rates that we can attribute to reduced liquid water content of the frozen soil. We conclude that the microbial population in boreal forest soil has the capacity to metabolize, and grow, on polymeric substrates at temperatures below zero, which involves maintaining exoenzymatic activity in frozen soils. This capacity manifests the importance of SOM mineralization during the winter season and its importance for the net carbon balance of

  2. Atomic-scale modeling of cellulose nanocrystals

    Science.gov (United States)

    Wu, Xiawa

    Cellulose nanocrystals (CNCs), the most abundant nanomaterials in nature, are recognized as one of the most promising candidates to meet the growing demand of green, bio-degradable and sustainable nanomaterials for future applications. CNCs draw significant interest due to their high axial elasticity and low density-elasticity ratio, both of which are extensively researched over the years. In spite of the great potential of CNCs as functional nanoparticles for nanocomposite materials, a fundamental understanding of CNC properties and their role in composite property enhancement is not available. In this work, CNCs are studied using molecular dynamics simulation method to predict their material' behaviors in the nanoscale. (a) Mechanical properties include tensile deformation in the elastic and plastic regions using molecular mechanics, molecular dynamics and nanoindentation methods. This allows comparisons between the methods and closer connectivity to experimental measurement techniques. The elastic moduli in the axial and transverse directions are obtained and the results are found to be in good agreement with previous research. The ultimate properties in plastic deformation are reported for the first time and failure mechanism are analyzed in details. (b) The thermal expansion of CNC crystals and films are studied. It is proposed that CNC film thermal expansion is due primarily to single crystal expansion and CNC-CNC interfacial motion. The relative contributions of inter- and intra-crystal responses to heating are explored. (c) Friction at cellulose-CNCs and diamond-CNCs interfaces is studied. The effects of sliding velocity, normal load, and relative angle between sliding surfaces are predicted. The Cellulose-CNC model is analyzed in terms of hydrogen bonding effect, and the diamond-CNC model compliments some of the discussion of the previous model. In summary, CNC's material properties and molecular models are both studied in this research, contributing to

  3. Complete dechlorination of pentachlorophenol using palladized bacterial cellulose in a rotating catalyst contact reactor.

    Science.gov (United States)

    Patel, Upendra D; Suresh, Sumathi

    2008-03-15

    A rotating catalyst contact reactor (RCCR) was developed which consisted of palladized bacterial cellulose immobilized on acrylic discs for hydrodechlorination of pentachlorophenol (PCP). More than 99% of 40 mg L(-1) PCP was dechlorinated to phenol in the presence of hydrogen in batch mode at initial pH values of 5.5 and 6.5 within 2 h of reaction with stoichiometric release of free chloride. The rate of PCP dechlorination was found to be independent of rotational speed of discs. PCP (40 mg L(-1)) hydrodechlorination experiments were also conducted using RCCR in continuous flow mode at hydraulic retention times of 1 and 2 h. The average outlet PCP concentrations revealed that liquid phase in RCCR closely resembled that of a continuous flow complete mix reactor (CFMR). Approximately 12 and 11 L of 40 mg L(-1) PCP (pH 6.5) could be treated in RCCR with 99 and 80% efficiencies in batch and continuous flow modes, respectively without any appreciable loss of the catalytic activity. These results suggested reusability of palladized bacterial cellulose which in turn is expected to substantially reduce the cost of treatment process. Thus RCCR seems to have high potential for treatment of ground water contaminated with chlorinated organic compounds. Dried palladized bacterial cellulose has been used as a material for electrodes in a fuel cell. However, its application as a hydrodechlorination catalyst in a reactor operating under room temperature and atmospheric pressure has not been reported to the best of our knowledge. Scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction analyses suggested the irreversible deposition of palladium (Pd 0) particles on the bacterial cellulose fibrils.

  4. Temperature responsive hydroxypropyl cellulose for encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Heitfeld, Kevin A.; Guo, Tingtai; Yang, George; Schaefer, Dale W. (UCIN)

    2009-08-26

    This work focuses on the use of temperature responsive gels (TRGs) (polymeric hydrogels with a large temperature-dependent change in volume) for flavor retention at cooking temperatures. Specifically, we have studied a gel with a lower critical solution temperature (LCST) that swells at low temperatures and collapses at high temperatures. In the collapsed state, the polymer acts as a transport barrier, keeping the volatile flavors inside. We have successfully synthesized a cellulose gel that exhibits this volume change and have encapsulated an oil phase inside the gel. The flavor-loaded encapsulated oil exhibited an increased release time when compared to similar gelatin capsules.

  5. Mechanical Properties of Cellulose Microfiber Reinforced Polyolefin

    Science.gov (United States)

    Kobayashi, Satoshi; Yamada, Hiroyuki

    Cellulose microfiber (CeF) has been expected as a reinforcement of polymer because of its high modulus and strength and lower cost. In the present study, mechanical properties of CeF/polyolefin were investigated. Tensile modulus increased with increasing CeF content. On the other hand, tensile strength decreased. Fatigue properties were also investigated with acoustic emission measurement. Stiffness of the composites gradually decreased with loading. Drastic decrease in stiffness was observed just before the final fracture. Based on the Mori-Tanaka's theory, the method to calculate modulus of CeF were proposed to evaluate dispersion of CeF.

  6. A Sorption Hysteresis Model For Cellulosic Materials

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Damkilde, Lars

    2006-01-01

    The equilibrium concentration of adsorbed water in cellulosic materials is dependent on the history of the variations of vapor pressure in the ambient air, i.e. sorption hysteresis. Existing models to describe this phenomenon such as the independent domain theory have numerical drawbacks and....../or imply accounting for the entire history variations of every material point. This paper presents a sorption hysteresis model based on a state formulation and expressed in closed-form solutions, which makes it suitable for implementation into a numerical method....

  7. Formation of carboxymethyl cellulose hydrogel containing silver nanoparticle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Seok; Kuang, Jia; Gwon, Hui Jeong; Lim, Youn Mook; Nho, Young Chang [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2010-12-15

    Silver nanoparticles (AgNPs) can be used in the areas such as integrate circuit, cell electrode and antimicrobial deodorant. In this study, AgNPs have been prepared by using AgNO{sub 3} aqueous solution in the carboxymethyl cellulose (CMC) hydrogel. CMC powders were dissolved in deionized water, and then irradiated by a gamma-ray with a radiation dose of 50 kGy to make CMC hydrogel. CMC hydrogels were dipped into 1.0 x 10{sup -2} M AgNO{sub 3} solution for 1 hour. After that, the swollen hydrogels were irradiated by gamma-ray for the formation of AgNPs. The characteristics of silver nanoparticles in the CMC hydrogels were monitored by UV-Vis and the morphological study and dispersed coefficient of particles were investigated by FE-SEM/EDX. It was observed that the sodium salt in the CMC is crucial to the formation of silver nanoparticle. Finally, antibacterial tests indiacted that the hydrogel containing silver nanoparticle has antibacterial activity.

  8. Understanding plant cellulose synthases through a comprehensive investigation of the cellulose synthase family sequences.

    Directory of Open Access Journals (Sweden)

    Andrew eCarroll

    2011-03-01

    Full Text Available The development of cellulose as an organizing structure in the plant cell wall was a key event in both the initial colonization and the subsequent domination of the terrestrial ecosystem by vascular plants. A wealth of experimental data has demonstrated the complicated genetic interactions required to form the large synthetic complex that synthesizes cellulose. However, these results are lacking an extensive analysis of the evolution, specialization, and regulation of the proteins that compose this complex. Here we perform an in-depth analysis of the sequences in the cellulose synthase (CesA family. We investigate the phylogeny of the CesA family, with emphasis on evolutionary specialization. We define specialized subfamilies and identify the class-specific regions within the CesA sequence that may explain this specialization. We investigate changes in regulation of CesAs by looking at the conservation of proposed phosphorylation sites. We investigate the conservation of sites where mutations have been documented that impair cellulose synthase function, and compare these sites to those observed in the closest cellulose synthase-like (Csl families to better understand what regions may separate the CesAs from other Csls. Finally we identify two positions with strong conservation of the aromatic trait, but lacking conservation of amino acid identity, which may represent residues important for positioning the sugar substrate for catalysis. These analyses provide useful tools for understanding characterized mutations and post-translational modifications, and for informing further experiments to probe CesA assembly, regulation, and function through site-directed mutagenesis or domain swapping experiments.

  9. Methods of detection using a cellulose binding domain fusion product

    Energy Technology Data Exchange (ETDEWEB)

    Shoseyov, Oded (Shimshon, IL); Shpiegl, Itai (North Gallilea, IL); Goldstein, Marc A. (Davis, CA); Doi, Roy H. (Davis, CA)

    1999-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  10. Development and Characterization of Cellulose/clay Nanocomposites

    Science.gov (United States)

    Cotton is the most important textile fiber for apparel use and is preferred to synthetic fibers for reasons such as comfort and feel. A major drawback of cellulosic fibers is flammability. The development of cellulose/clay nanocomposites for use as flame retardant materials based on cotton is repo...

  11. Cellulose-Lignin interactions during slow and fast pyrolysis

    NARCIS (Netherlands)

    Hilbers, T.J.; Wang, Z.; Pecha, B.; Westerhof, R.J.M.; Kersten, S.R.A.; Pelaez-Samaniego, M.R.; Garcia-Perez, M.

    2015-01-01

    The interactions between lignin and cellulose during the slow pyrolysis of their blends were studied by means of Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). Fast pyrolysis was studied using Pyrolysis-Gas Chromatography/Mass Spectroscopy (Py–GC/MS). Crystalline cellulose

  12. Life Cycle Assessment of man-made cellulose fibres

    NARCIS (Netherlands)

    Shen, L.; Patel, M.K.

    2010-01-01

    The production of textile materials has undergone dramatic changes in the last century. Man-made cellulose fibres have played an important role for more than 70 years. Today, the man-made cellulose fibre industry is the worldwide second largest biorefinery (next to the paper industry). In the last f

  13. Environmental impact assessment of man-made cellulose fibres

    NARCIS (Netherlands)

    Shen, L.; Worrell, E.; Patel, M.K.

    2010-01-01

    Man-made cellulose fibres have played an important role in the production of textile products for more than 70 years. The purpose of this study is to assess the environmental impact of man-made cellulose fibres. Life cycle assessment (LCA) was conducted for three types of fibres (i.e. Viscose, Modal

  14. Single Molecule Study of Cellulase Hydrolysis of Crystalline Cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.-S.; Luo, Y.; Baker, J. O.; Zeng, Y.; Himmel, M. E.; Smith, S.; Ding, S.-Y.

    2009-12-01

    This report seeks to elucidate the role of cellobiohydrolase-I (CBH I) in the hydrolysis of crystalline cellulose. A single-molecule approach uses various imaging techniques to investigate the surface structure of crystalline cellulose and changes made in the structure by CBH I.

  15. Methods of use of cellulose binding domain proteins

    Science.gov (United States)

    Shoseyov, Oded; Shpiegl, Itai; Goldstein, Marc A.; Doi, Roy H.

    1997-01-01

    A cellulose binding domain (CBD) having a high affinity for crystalline cellulose and chitin is disclosed, along with methods for the molecular cloning and recombinant production thereof. Fusion products comprising the CBD and a second protein are likewise described. A wide range of applications are contemplated for both the CBD and the fusion products, including drug delivery, affinity separations, and diagnostic techniques.

  16. Cellulose synthesizing Complexes in Vascular Plants andProcaryotes

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Richard M, Jr; Saxena, Inder Mohan

    2009-07-07

    Continuing the work initiated under DE-FG03-94ER20145, the following major accomplishments were achieved under DE-FG02-03ER15396 from 2003-2007: (a) we purified the acsD gene product of the Acetobacter cellulose synthase operon as well as transferred the CesA cellulose gene from Gossypium into E. coli in an attempt to crystallize this protein for x-ray diffraction structural analysis; however, crystallization attempts proved unsuccessful; (b) the Acetobacter cellulose synthase operon was successfully incorporated into Synechococcus, a cyanobacterium2; (c) this operon in Synechococcus was functionally expressed; (d) we successfully immunolabeled Vigna cellulose and callose synthase components and mapped their distribution before and after wounding; (e) we developed a novel method to produce replicas of cellulose synthases in tobacco BY-2 cells, and we demonstrated the cytoplasmic domain of the rosette TC; (f) from the moss Physcomitrella, we isolated two full-length cDNA sequences of cellulose synthase (PpCesA1 and PpCesA2) and attempted to obtain full genomic DNA sequences; (g) we examined the detailed molecular structure of a new form of non-crystalline cellulose known as nematic ordered cellulose (=NOC)3.

  17. Characterization of cellulose based sponges for wound dressings

    NARCIS (Netherlands)

    Gustaite, S.; Kazlauske, J.; Bobokalonov, J.; Perni, S.; Dutschk, V.; Liesiene, J.; Prokopovich, P.

    2015-01-01

    Cellulose based sponges were developed by freeze-drying of regenerated cellulose gels and characterizedas a potential wound dressing. Morphological characteristics were analyzed by means of micro-computedtomography. The results showed that the porosity of the sponges reached 75%, the pores were inte

  18. Molecular weights of cellulose nitrates by osmotic pressure measurements

    Directory of Open Access Journals (Sweden)

    dr. V. Subramanyam

    1950-04-01

    Full Text Available It is well-known that nitro celluloses are employed for a variety of purposes. Broadly  nitrocellulose with relatively high nitrogen content are used in propellant and explosive manufacture nitrocelluloses  with lower nitrogen content find application in celluloid, in the lacquer industry, in cellulose paints, etc.

  19. Recent Development in Spectroscopic and Chemical Characterization of Cellulose

    Science.gov (United States)

    2005-01-01

    the I β form. As noted earlier, the nomenclature chosen was intended to avoid confusion with the IA and IB forms previously used to clas- sify the...cellulose suspended in a mixture of acetic anhydride / acetic acid/H2SO4 around 60°C. Cellulose triacetate is soluble in chlorinated hydrocarbons such as

  20. Cellulose: A review as natural, modified and activated carbon adsorbent.

    Science.gov (United States)

    Suhas; Gupta, V K; Carrott, P J M; Singh, Randhir; Chaudhary, Monika; Kushwaha, Sarita

    2016-09-01

    Cellulose is a biodegradable, renewable, non-meltable polymer which is insoluble in most solvents due to hydrogen bonding and crystallinity. Natural cellulose shows lower adsorption capacity as compared to modified cellulose and its capacity can be enhanced by modification usually by chemicals. This review focuses on the utilization of cellulose as an adsorbent in natural/modified form or as a precursor for activated carbon (AC) for adsorbing substances from water. The literature revealed that cellulose can be a promising precursor for production of activated carbon with appreciable surface area (∼1300m(2)g(-1)) and total pore volume (∼0.6cm(3)g(-1)) and the surface area and pore volume varies with the cellulose content. Finally, the purpose of review is to report a few controversies and unresolved questions concerning the preparation/properties of ACs from cellulose and to make aware to readers that there is still considerable scope for future development, characterization and utilization of ACs from cellulose.

  1. CELLULOSE EXTRACTION FROM PALM KERNEL CAKE USING LIQUID PHASE OXIDATION

    Directory of Open Access Journals (Sweden)

    FARM YAN YAN

    2009-03-01

    Full Text Available Cellulose is widely used in many aspect and industries such as food industry, pharmaceutical, paint, polymers, and many more. Due to the increasing demand in the market, studies and work to produce cellulose are still rapidly developing. In this work, liquid phase oxidation was used to extract cellulose from palm kernel cake to separate hemicellulose, cellulose and lignin. The method is basically a two-step process. Palm kernel cake was pretreated in hot water at 180°C and followed by liquid oxidation process with 30% H2O2 at 60°C at atmospheric pressure. The process parameters are hot water treatment time, ratio of palm kernel cake to H2O2, liquid oxidation reaction temperature and time. Analysis of the process parameters on production cellulose from palm kernel cake was performed by using Response Surface Methodology. The recovered cellulose was further characterized by Fourier Transform Infrared (FTIR. Through the hot water treatment, hemicellulose in the palm kernel cake was successfully recovered as saccharides and thus leaving lignin and cellulose. Lignin was converted to water soluble compounds in liquid oxidation step which contains small molecular weight fatty acid as HCOOH and CH3COOH and almost pure cellulose was recovered.

  2. Endurance of high molecular weight carboxymethyl cellulose in corrosive environments

    Science.gov (United States)

    Murodov, M. M.; Rahmanberdiev, G. R.; Khalikov, M. M.; Egamberdiev, E. A.; Negmatova, K. C.; Saidov, M. M.; Mahmudova, N.

    2012-07-01

    Lignin obtained from the waste cooking liquor, formed after soda pulping process, is used as an inhibitor of NaCMC thermo oxidative degradation in presence of in extreme conditions during drilling oil wells. In this paper the schematic process of obtaining NaCMC by the principle of "monoapparat" on the basis of cellulose produced by non-wood cellulose materials is presented.

  3. Carbon-supported base metal nanoparticles : Cellulose at work

    NARCIS (Netherlands)

    Hoekstra, Jacco; Versluijs-Helder, Marjan; Vlietstra, Edward J.; Geus, John W.; Jenneskens, Leonardus W.

    2015-01-01

    Pyrolysis of base metal salt loaded microcrystalline cellulose spheres gives a facile access to carbon-supported base metal nanoparticles, which have been characterized with temperature-dependent XRD, SEM, TEM, ICP-MS and elemental analysis. The role of cellulose is multifaceted: 1) it facilitates a

  4. Cellulose nanocrystal interactions probed by thin film swelling to predict dispersibility

    Science.gov (United States)

    Reid, Michael S.; Villalobos, Marco; Cranston, Emily D.

    2016-06-01

    The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of the interactions between components. Measuring the cohesive particle-particle interactions and the adhesive particle-polymer interactions is challenging due to nanoscale dimensions and poor colloidal stability of nanoparticles in many solvents. We demonstrate a new cohesive interaction measurement method using cellulose nanocrystals (CNCs) as a model system; CNCs have recently gained attention in the composites community due to their mechanical strength and renewable nature. Multi-wavelength surface plasmon resonance spectroscopy (SPR) was used to monitor the swelling of CNC thin films to elucidate the primary forces between CNCs. This was achieved by measuring swelling in situ in water, acetone, methanol, acetonitrile, isopropanol, and ethanol and relating the degree of swelling to solvent properties. Films swelled the most in water where we estimate 1.2-1.6 nm spacings between CNCs (or 4-6 molecular layers of water). Furthermore, a correlation was found between film swelling and the solvent's Hildebrand solubility parameter (R2 = 0.9068). The hydrogen bonding component of the solubility parameters was more closely linked to swelling than the polar or dispersive components. The films remained intact in all solvents, and using DLVO theory we have identified van der Waals forces as the main cohesive interaction between CNCs. The trends observed suggest that solvents (and polymers) alone are not sufficient to overcome CNC-CNC cohesion and that external energy is required to break CNC agglomerates. This work not only demonstrates that SPR can be used as a tool to measure cohesive particle-particle interactions but additionally advances our fundamental understanding of CNC interactions which is necessary for the design of cellulose nanocomposites.The production of well-dispersed reinforced polymer nanocomposites has been limited due to poor understanding of

  5. Compactibility of mixtures of calcium carbonate and microcrystalline cellulose.

    Science.gov (United States)

    Garzón, M de Lourdes; Villafuerte, Leopoldo

    2002-01-01

    A patented coprocessed mixture of microcrystalline cellulose (MC) and calcium carbonate (CC) is claimed to perform, as a pharmaceutical excipient, equal or better than pure MC. To investigate it, the tensile strength (T) of tablets made of mixtures of MC type 102, CC, magnesium stearate (MS) and polyvinylpyrrolidone (PVP) and formed under a compaction pressure (P(c)) ranging up to 618 MPa has been determined. The compactibility of the mixtures was defined through regression parameters obtained with ln(-ln(1-T/T(max)))=slope x lnP(c) + intercept. MC/CC mixtures, P(c)=618 MPa, show a small decrease in tablet tensile strength with CC proportions up to about 20%, falling considerably thereafter. Lower compaction pressures, P(c)tablet tensile strength due to 2%-MS, P(c)=487 MPa, was recovered to 35% of its original value admixing about 25% CC. This maximal value of recovery showed a shift to lower proportions of CC, up to 10%, as compaction pressure decreased. This was attributed to lower CC-particles fragmentation or agglomerates spreading at lower compaction pressures. Mixtures with increased plasticity (MC/CC/PVP and MC/CC/PVP/MS) showed an increased compactibility, which was more evident at higher compaction pressures and higher CC proportions, presumably due to higher deformation and erosion of PVP particles. Inclusion of about 40% CC in a MC/PVP/MS mixture showed 60% recovery of the original MC tablet tensile strength. Lower MS proportions are expected to allow a higher recovery.

  6. In vitro synthesis of cellulose microfibrils by a membrane protein from protoplasts of the non-vascular plant Physcomitrella patens.

    Science.gov (United States)

    Cho, Sung Hyun; Du, Juan; Sines, Ian; Poosarla, Venkata Giridhar; Vepachedu, Venkata; Kafle, Kabindra; Park, Yong Bum; Kim, Seong H; Kumar, Manish; Nixon, B Tracy

    2015-09-01

    Plant cellulose synthases (CesAs) form a family of membrane proteins that are associated with hexagonal structures in the plasma membrane called CesA complexes (CSCs). It has been difficult to purify plant CesA proteins for biochemical and structural studies. We describe CesA activity in a membrane protein preparation isolated from protoplasts of Physcomitrella patens overexpressing haemagglutinin (HA)-tagged PpCesA5. Incubating the membrane preparation with UDP-glucose predominantly produced cellulose. Negative-stain EM revealed microfibrils. Cellulase bound to and degraded these microfibrils. Vibrational sum frequency generation (SFG) spectroscopic analysis detected the presence of crystalline cellulose in the microfibrils. Putative CesA proteins were frequently observed attached to the microfibril ends. Combined cross-linking and gradient centrifugation showed bundles of cellulose microfibrils with larger particle aggregates, possibly CSCs. These results suggest that P. patens is a useful model system for biochemical and structural characterization of plant CSCs and their components.

  7. Cellulose-reinforced composites: from micro-to nanoscale

    Directory of Open Access Journals (Sweden)

    Alain Dufresne

    2013-01-01

    Full Text Available This paper present the most relevant advances in the fields of: i cellulose fibres surface modification; ii cellulose fibres-based composite materials; and iii nanocomposites based on cellulose whiskers or starch platelet-like nanoparticles. The real breakthroughs achieved in the first topic concern the use of solvent-free grafting process (plasma and the grafting of the matrix at the surface of cellulose fibres through isocyanate-mediated grafting or thanks to "click chemistry". Concerning the second topic, it is worth to mention that for some cellulose/matrix combination and in the presence of adequate aids or specific surface treatment, high performance composite materials could be obtained. Finally, nanocomposites allow using the semi-crystalline nature and hierarchical structure of lignocellulosic fibres and starch granules to more deeply achieve this goal profitably exploited by Mother Nature

  8. Cellulose destruction under successive thermal and radiation treatment. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ershov, B.G.; Komarov, V.B.

    1985-02-01

    The influence of successive thermal and radiation effect on cellulose is investigated. The samples were ..gamma.. irradiated (/sup 60/Co) with a dose rate of 20 kGy/h (the absorbed doses ranged from 0 to 80 kGy) and heated up to 190 deg C. It is shown that the attainment of the same destruction depth for the heated-up cellulose occurs at noticeably lower absorbed doses than for the cellulose which has not been subjected to thermal treatment. For successive thermal and radiation treatment of cellulose the ratio S=S therm.+Ssub(rad) where S is a number of broken bonds in a macromolecule is correct. The radiation-chemical yield of cellulose destruction is determined to be: G=7.3 +- 0.1 mol/100 eV.

  9. Experimental study on cellulose particulate and its composites

    Science.gov (United States)

    Srinivasababu, Nadendla

    2016-05-01

    Anselme Payen has discovered cellulose after conducting rigorous experiments on wood. In this work an attempt is made to reinforce cellulose particulate into polyester matrix from 1.84 - 9.18 wt % and the lamina is manufactured by JMFIL technique. The fabricated lamina is cut into specimens for various tests as per ASTM standards. Tensile strength of 22.61 MPa is achieved at 1.84 % of cellulose content in composites. Then the cellulose composites at 1.89% of reinforcement level showed 55.57 MPa, 1.86 GPa flexural strength, modulus respectively. `C' kind of failure is visualized for all the specimens and volume fractions during impact test. The cellulose particulate is also analyzed for its morphology, size.

  10. Employing ionic liquids to deposit cellulose on PET fibers.

    Science.gov (United States)

    Textor, Torsten; Derksen, Leonie; Gutmann, Jochen S

    2016-08-01

    Several ionic liquids are excellent solvents for cellulose. Starting from that finishing of PET fabrics with cellulose dissolved in ionic liquids like 1-ethyl-3-methyl imidazolium acetate, diethylphosphate and chloride, or the chloride of butyl-methyl imidazolium has been investigated. Finishing has been carried out from solutions of different concentrations, using microcrystalline cellulose or cotton and by employing different cross-linkers. Viscosity of solutions has been investigated for different ionic liquids, concentrations, cellulose sources, linkers and temperatures. Since ionic liquids exhibit no vapor pressure, simple pad-dry-cure processes are excluded. Before drying the ionic liquid has to be removed by a rinsing step. Accordingly rinsing with fresh ionic liquid followed by water or the direct rinsing with water have been tested. The amount of cellulose deposited has been investigated by gravimetry, zinc chloride iodine test as well as reactive dyeing. Results concerning wettability, water up-take, surface resistance, wear-resistance or washing stability are presented.

  11. Physical properties of agave cellulose graft polymethyl methacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan [Polymer Research Centre (PORCE), School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi Selangor (Malaysia)

    2013-11-27

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  12. Physical properties of agave cellulose graft polymethyl methacrylate

    Science.gov (United States)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-01

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm-1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  13. The Solubility of Natural Cellulose After DBD Plasma Treatment

    Institute of Scientific and Technical Information of China (English)

    WU Jun; ZENG Fengcai; CHEN Bingqiang

    2008-01-01

    Natural cellulose was treated by an atmospheric DBD plasma. The solubility of cel-lulose in a diluted alkaline solution after the plasma treatment was investigated. The properties were characterized by X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spec-troscopy (FTIR) and scanning electron microscopy (SEM). The results indicated that the surface of cellulose treated by the argon DBD plasma was significantly etched, and the relevant force of hy-drogen bonding was decreased. This might be the essential reason for the solubility improvement of natural cellulose in the diluted alkaline solution. Through a comparison of two discharge modes, the atmospheric DBD plasma gun and the parallel plate capacitively coupled DBD plasma, it wasfound that the atmospheric DBD plasma gun was more effective in fragmentizing the cellulose due to its production of a high energy plasma based on its special structure [6] .

  14. Multifilament cellulose/chitin blend yarn spun from ionic liquids.

    Science.gov (United States)

    Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R

    2015-10-20

    Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, cellulose/chitin blend fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers.

  15. Regenerated cellulose/wool blend enhanced biomimetic hydroxyapatite mineralization.

    Science.gov (United States)

    Salama, Ahmed; El-Sakhawy, Mohamed

    2016-11-01

    The current article investigates the effect of bioactive cellulose/wool blend on calcium phosphate biomimetic mineralization. Regenerated cellulose/wool blend was prepared by dissolution-regeneration of neat cellulose and natural wool in 1-butyl-3-methyl imidazolium chloride [Bmim][Cl], as a solvent for the two polymers. Crystalline hydroxyapatite nanofibers with a uniform size, shape and dimension were formed after immersing the bioactive blend in simulated body fluid. The cytotoxicity of cellulose/wool/hydroxyapatite was studied using animal fibroblast baby hamster kidney cells (BHK-21) and the result displayed good cytocompatability. This research work presents a green processing method for the development of novel cellulose/wool/hydroxyapatite hybrid materials for tissue engineering applications.

  16. Loosening Xyloglucan Accelerates the Enzymatic Degradation of Cellulose in Wood

    Institute of Scientific and Technical Information of China (English)

    Rumi Kaida; Tomomi Kaku; Kei'ichi Baba; Masafumi Oyadomari; Takashi Watanabe; Koji Nishida; Toshiji Kanaya; Ziv Shani; Oded Shoseyov; Takahisa Hayashi

    2009-01-01

    In order to create trees in which cellulose, the most abundant component in biomass, can be enzymatically hydrolyzed highly for the production of bioethanol, we examined the saccharification of xylem from several transgenic poplars, each overexpressing either xyloglucanase, cellulase, xylanase, or galactanase. The level of cellulose degradation achieved by a cellulase preparation was markedly greater in the xylem overexpressing xyloglucanase and much greater in the xylems overexpressing xylanase and cellulase than in the xylem of the wild-type plant. Although a high degree of degradation occurred in all xylems at all loci, the crystalline region of the cellulose microfibrUs was highly degraded in the xylem overexpressing xyloglucanase. Since the complex between microfibrils and xyloglucans could be one region that is particularly resistant to cellulose degradation, loosening xyloglucan could facilitate the enzymatic hydrolysis of cellulose in wood.

  17. In-situ glyoxalization during biosynthesis of bacterial cellulose.

    Science.gov (United States)

    Castro, Cristina; Cordeiro, Nereida; Faria, Marisa; Zuluaga, Robin; Putaux, Jean-Luc; Filpponen, Ilari; Velez, Lina; Rojas, Orlando J; Gañán, Piedad

    2015-08-01

    A novel method to synthesize highly crosslinked bacterial cellulose (BC) is reported. The glyoxalization is started in-situ, in the culture medium during biosynthesis of cellulose by Gluconacetobacter medellensis bacteria. Strong crosslinked networks were formed in the contact areas between extruded cellulose ribbons by reaction with the glyoxal precursors. The crystalline structure of cellulose was preserved while the acidic component of the surface energy was reduced. As a consequence, its predominant acidic character and the relative contribution of the dispersive component increased, endowing the BC network with a higher hydrophobicity. This route for in-situ crosslinking is expected to facilitate other modifications upon biosynthesis of cellulose ribbons by microorganisms and to engineer the strength and surface energy of their networks.

  18. NANOCOMPOSITES OF POLY(LACTIC ACID REINFORCED WITH CELLULOSE NANOFIBRILS

    Directory of Open Access Journals (Sweden)

    Liping Zhang

    2010-06-01

    Full Text Available A chemo-mechanical method was used to prepare cellulose nanofibrils dispersed uniformly in an organic solvent. Poly(ethylene glycol (PEG 1000 was added to the matrix as a compatibilizer to improve the interfacial interaction between the hydrophobic poly(lactic acid (PLA and the hydrophilic cellulose nanofibrils. The composites obtained by solvent casting methods from N,N-Dimethylacetamide (DMAc were characterized by tensile testing machine, atomic force microscope (AFM, scanning electron microscope (SEM, and Fourier transform infrared spectroscopy (FT-IR. The tensile test results indicated that, by adding PEG to the PLA and the cellulose nanofibrils matrix, the tensile strength and the elongation rate increased by 56.7% and 60%, respectively, compared with the PLA/cellulose nanofibrils composites. The FT-IR analysis successfully showed that PEG improved the intermolecular interaction, which is based on the existence of inter-molecular hydrogen bonding among PLA, PEG, and cellulose nanofibrils.

  19. Production of ethanol from cellulose using Clostridum thermocellum

    Energy Technology Data Exchange (ETDEWEB)

    Zertuche, L.; Zall, R.R.

    1982-01-01

    Clostridium thermocellum was used to produce ethanol from cellulose in a continuous system. Batch fermentations were first performed to observe the effects of buffers and agitation on generation time and ethanol production. Continuous fermentations were carried out at 60/sup 0/C and pH 7 using pure cellulose as the limiting substrate. The maximum ethanol concentrations produced with 1.5 and 3% cellulose fermenting liquid were 0.3 and 0.9% respectively. The yield of ethanol was about 0.3 grams per gram of cellulose consumed. While the continuous fermentaion of cellulose with Clostridium thermocellum appears to be feasible, it may not be economically promising due to the slow growth of the organism.

  20. Dissolution of cellulose in ionic liquid: A review

    Science.gov (United States)

    Mohd, N.; Draman, S. F. S.; Salleh, M. S. N.; Yusof, N. B.

    2017-02-01

    Dissolution of cellulose with ionic liquids (IL) and deep eutectic solvent (DES) lets the comprehensive dissolution of cellulose. Basically, cellulose can be dissolved, in some hydrophilic ionic liquids, such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and 1-allyl-3-methylimidazolium chloride (AMIMCl). Chloride based ionic liquids are suitable solvents for cellulose dissolution. Although the ILs is very useful in fine chemical industry, its application in the pharmaceutical and food industry have been very limited due to issues with toxicity, purity, and high cost. Seeing to these limitations, new green alternative solvent which is DES was used. This green solvents, may be definitely treated as the next-generation reagents for more sustainable industrial development. Thus, this review aims to discuss the dissolution of cellulose either with ionic liquids or DES and its application.

  1. Titanium dioxide-cellulose hybrid nanocomposite based conductometric glucose biosensor

    Science.gov (United States)

    Maniruzzaman, Mohammad; Mahadeva, Suresha K.; Khondoker, Abu Hasan; Kim, Jaehwan

    2012-04-01

    This paper investigates the feasibility of conductometric glucose biosensor based on glucose oxidase (GOx) immobilized TiO2-cellulose hybrid nanocomposite. TiO2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N, N-dimethylacetamide solvent to fabricate TiO2-cellulose hybrid nanocomposite. The enzyme (GOx) was immobilized into this hybrid material by physical adsorption method. The successful immobilization of GOx into TiO2-cellulose hybrid nanocomposite via covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of our propose glucose biosensor is obtained in the range of 1-10mM with correlation coefficient of 0.93. Our study demonstrates TiO2-cellulose hybrid material as a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  2. Communication and Sensing Circuits on Cellulose

    Directory of Open Access Journals (Sweden)

    Federico Alimenti

    2015-06-01

    Full Text Available This paper proposes a review of several circuits for communication and wireless sensing applications implemented on cellulose-based materials. These circuits have been developed during the last years exploiting the adhesive copper laminate method. Such a technique relies on a copper adhesive tape that is shaped by a photo-lithographic process and then transferred to the hosting substrate (i.e., paper by means of a sacrificial layer. The presented circuits span from UHF oscillators to a mixer working at 24 GHz and constitute an almost complete set of building blocks that can be applied to a huge variety communication apparatuses. Each circuit is validated experimentally showing performance comparable with the state-of-the-art. This paper demonstrates that circuits on cellulose are capable of operating at record frequencies and that ultra- low cost, green i.e., recyclable and biodegradable materials can be a viable solution to realize high frequency hardware for the upcoming Internet of Things (IoT era.

  3. Net energy of cellulosic ethanol from switchgrass.

    Science.gov (United States)

    Schmer, M R; Vogel, K P; Mitchell, R B; Perrin, R K

    2008-01-15

    Perennial herbaceous plants such as switchgrass (Panicum virgatum L.) are being evaluated as cellulosic bioenergy crops. Two major concerns have been the net energy efficiency and economic feasibility of switchgrass and similar crops. All previous energy analyses have been based on data from research plots (biomass energy crop in field trials of 3-9 ha (1 ha = 10,000 m2) on marginal cropland on 10 farms across a wide precipitation and temperature gradient in the midcontinental U.S. to determine net energy and economic costs based on known farm inputs and harvested yields. In this report, we summarize the agricultural energy input costs, biomass yield, estimated ethanol output, greenhouse gas emissions, and net energy results. Annual biomass yields of established fields averaged 5.2-11.1 Mg x ha(-1) with a resulting average estimated net energy yield (NEY) of 60 GJ x ha(-1) x y(-1). Switchgrass produced 540% more renewable than nonrenewable energy consumed. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY than previous estimates from human-made prairies that received low agricultural inputs. Estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than estimated GHG from gasoline. This is a baseline study that represents the genetic material and agronomic technology available for switchgrass production in 2000 and 2001, when the fields were planted. Improved genetics and agronomics may further enhance energy sustainability and biofuel yield of switchgrass.

  4. Modification of cellulose for high glucose generation.

    Science.gov (United States)

    Jiang, Xue; Gu, Jian; Tian, Xiuzhi; Li, Yali; Huang, Dan

    2012-01-01

    The influence of introduction of cyanuric chloride on glucose's yield (Y) in acid-catalyzed hydrolysis of microcrystalline cellulose (MCC) has been studied. The content of cyanuric chloride (C) in modified MCCs was determined by X-ray photoelectric spectroscopy. The chemical structures of modified MCCs were analyzed by Fourier transformation-infrared spectroscopy and cross polarization/magic angle spinning (13)C nuclear magnetic resonance. Crystal index (CI) and the ratio (R) representing the sum of content of (1 ̅10) and (110) to that of (200) were calculated based on diffraction intensity in wide angle X-ray diffraction (WAXD). Hydrolysis experiment and WAXD show that Y, CI and R vary with C. The modified MCC containing 3.9 mol% of cyanuric chloride has the highest Y, the highest R and the lowest CI. Variations of CI and R show that the chemical modification changed the proportion of crystal/amorphous and crystal planes, both of which influence glucose's generation in hydrolysis of cellulose.

  5. Starch composites reinforced by bamboo cellulosic crystals.

    Science.gov (United States)

    Liu, Dagang; Zhong, Tuhua; Chang, Peter R; Li, Kaifu; Wu, Qinglin

    2010-04-01

    Using a method of combined HNO(3)-KClO(3) treatment and sulfuric acid hydrolysis, bamboo cellulose crystals (BCCs) were prepared and used to reinforce glycerol plasticized starch. The structure and morphology of BCCs were investigated using X-ray diffraction, electron microscopy, and solid-state (13)C NMR. Results showed that BCCs were of typical cellulose I structure, and the morphology was dependent on its concentration in the suspension. BCC of 50-100 nm were assembled into leaf nervations at low concentration (i.e. 0.1 wt.% of solids), but congregated into a micro-sized "flower" geometry at high concentration (i.e. 10.0 wt.% of solids). Tensile strength and Young's modulus of the starch/BCC composite films (SBC) were enhanced by the incorporation of the crystals due to reinforcement of BCCs and reduction of water uptake. BCCs at the optimal 8% loading level exhibited a higher reinforcing efficiency for plasticized starch plastic than any other loading level.

  6. CELLULOSE DECOMPOSTION IN TROPICAL PEAT SWAMPS

    Institute of Scientific and Technical Information of China (English)

    Hjh Dulima Jali

    2003-01-01

    Given that organic soil is a complex substrate and there are many environmental factors which directly or indirectly control its decomposition processes, the use of standard substrate simplify the system in that the effect of substrate quality could be eliminated and influence of certain environmental conditions such as edaphic factors, acidity and moisture could be focused on. In addition to the forest floor, decomposition potential down the peat profile can also be examined. Cotton strip assay was used to estimate decomposition potentials in tropical peat swamp occupied by different Shorea Albida peat swamp forest communities, The' Alan Batu' , the ' Alan Bunga' , the' Alan Padang' and the 'mixed Alan'forest communities. Greatest decay rates on the peat surface took place during the wet period. The moist condition of the wet months appeared to favour the growth and stimulate activities of decomposer population and soil invertebrates.Generally, 50% of cotton tensile loss is achieved after four weeks of exposure. The results suggest that cellulose decomposition is influenced by the environmental variables of hydrological regime, water-table fluctuation, aeration, moisture availability,waterlogging and the resultant anaerobiosis, peat depths, and micro-sites characteristics. Decomposition of cellulose is inhibited by waterlogging and the resultant anaerobiosis in thelower segment of the cotton strip during wet periods and under dry conditions in the surface segment of the cotton strip during periods of less rain.

  7. Cellulose-hemicellulose interaction in wood secondary cell-wall

    Science.gov (United States)

    Zhang, Ning; Li, Shi; Xiong, Liming; Hong, Yu; Chen, Youping

    2015-12-01

    The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose.

  8. Characterization of blend hydrogels based on plasticized starch/cellulose acetate/carboxymethyl cellulose synthesized by electron beam irradiation

    Science.gov (United States)

    Senna, Magdy M.; Mostafa, Abo El-Khair B.; Mahdy, Sanna R.; El-Naggar, Abdel Wahab M.

    2016-11-01

    Blend hydrogels based on aqueous solutions of plasticized starch and different ratios of cellulose acetate (CA) and carboxymethyl cellulose (CMC) were prepared by electron beam irradiation (EB). The blends before and after EB irradiation were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The physico-chemical properties of blend hydrogels prepared by electron beam irradiation were improved compared to unirradiated blends.

  9. Immobilization of Glucose Oxidase on Cellulose/Cellulose Acetate Membrane and its Detection by Scanning Electrochemical Microscope (SECM)

    Institute of Scientific and Technical Information of China (English)

    Jin Sheng ZHAO; Zhen Yu YANG; Yi He ZHANG; Zheng Yu YANG

    2004-01-01

    Cellulose/cellulose acetate membranes were prepared and functionalized by introducing amino group on it, and then immobilized the glucose oxidase (Gox) on the functionalizd membrane. SECM was applied for the detection of enzyme activity immobilized on the membrane. Immobilized biomolecules on such membranes was combined with analysis apparatus and can be used in bioassays.

  10. Preparation of cellulose II and III{sub I} films by allomorphic conversion of bacterial cellulose I pellicles

    Energy Technology Data Exchange (ETDEWEB)

    Faria-Tischer, Paula C.S., E-mail: paula.tischer@pq.cnpq.br [BioPol, Departamento de Química, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); UMR 5628 (LMGP), CNRS and Grenoble Institute of Technology, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Tischer, Cesar A. [BioPol, Departamento de Química, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); CIME Nanotech, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Heux, Laurent [Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble (France); CNRS, CERMAV, F-38000 Grenoble (France); Le Denmat, Simon; Picart, Catherine [UMR 5628 (LMGP), CNRS and Grenoble Institute of Technology, 3 Parvis Louis Néel, F-38016 Grenoble Cedex 1 (France); Sierakowski, Maria-R. [BioPol, Departamento de Química, UFPR, Cx. Postal 19081, 81531-980 Curitiba, PR (Brazil); and others

    2015-06-01

    The structural changes resulting from the conversion of native cellulose I (Cel I) into allomorphs II (Cel II) and III{sub I} (Cel III{sub I}) have usually been studied using powder samples from plant or algal cellulose. In this work, the conversion of Cel I into Cel II and Cel III{sub I} was performed on bacterial cellulose films without any mechanical disruption. The surface texture of the films was observed by atomic force microscopy (AFM) and the morphology of the constituting cellulose ribbons, by transmission electron microscopy (TEM). The structural changes were characterized using solid-state NMR spectroscopy as well as X-ray and electron diffraction. The allomorphic change into Cel II and Cel III{sub I} resulted in films with different crystallinity, roughness and hydrophobic/hydrophilicity surface and the films remained intact during all process of allomorphic conversion. - Highlights: • Description of a method to modify the allomorphic structure of bacterial cellulose films • Preparation of films with specific morphologies and hydrophobic/hydrophilic surface characters • First report on cellulose III films from bacterial cellulose under swelling conditions • Detailed characterization of cellulose II and III films with complementary techniques • Development of films with specific properties as potential support for cells, enzymes, and drugs.

  11. Properties of films composed of cellulose nanowhiskers and a cellulose matrix regenerated from alkali/urea solution.

    Science.gov (United States)

    Qi, Haisong; Cai, Jie; Zhang, Lina; Kuga, Shigenori

    2009-06-01

    All-cellulose composite films were prepared, for the first time, from native cellulose nanowhiskers and cellulose matrix regenerated from aqueous NaOH-urea solvent system on the basis of their temperature-dependent solubility. The cellulose whiskers retained their needlelike morphology with mean length and diameter of 300 and 21 nm as well as native crystallinity when added to the latter solution at ambient temperature. The structure and physical properties of the nanocomposite films were characterized by scanning electron microscope, X-ray diffraction, and tensile tests. The composite films were isotropic and transparent to visible light and showed good mechanical properties as a result of the reinforcement by the whiskers. By varying the ratio of the cellulose whiskers to regenerated cellulose matrix (cellulose II), the tensile strength and elastic modulus of the nanocomposite films could be tuned to reach 124 MPa and 5 GPa, respectively. The tensile strength of the nanocomposite films could reach 157 MPa through a simple drawing process, with the calculated Hermans' orientation parameter of 0.30. This work provided a novel pathway for the preparation of biodegradable all-cellulose nanocomposites, which are expected to be useful as biomaterials and food ingredients.

  12. Use of recombinant cellulose-binding domains of Trichoderma reesei cellulase as a selective immunocytochemical marker for cellulose in protozoa.

    Science.gov (United States)

    Linder, Markus; Winiecka-Krusnell, Jadwiga; Linder, Ewert

    2002-05-01

    Some unicellular organisms are able to encyst as a protective response to a harmful environment. The cyst wall usually contains chitin as its main structural constituent, but in some cases, as in Acanthamoeba, it consists of cellulose instead. Specific cytochemical differentiation between cellulose and chitin by microscopy has not been possible, due to the similarity of their constituent beta-1,4-linked hexose backbones. Thus, various fluorescent brightening agents and lectins bind to both cellulose and chitin. We have used a recombinant cellulose-binding protein consisting of two cellulose-binding domains (CBDs) from Trichoderma reesei cellulases linked together in combination with monoclonal anticellulase antibodies and anti-mouse immunoglobulin fluorescein conjugate to specifically stain cellulose in the cysts of Acanthamoeba strains for fluorescence microscopy imaging. Staining was observed in ruptured cysts and frozen sections of cysts but not in intact mature cysts. No staining reaction was observed with the chitin-containing cyst walls of Giardia intestinalis, Entamoeba dispar, or Pneumocystis carinii. Thus, the recombinant CBD can be used as a marker to distinguish between cellulose and chitin. Thirteen of 25 environmental or clinical isolates of amoebae reacted in the CBD binding assay. All 13 isolates were identified as Acanthamoeba spp. Five isolates of Hartmannella and seven isolates of Naegleria tested negative in the CBD binding assay. Whether cyst wall cellulose really is a unique property of Acanthamoeba spp. among free-living amoebae, as suggested by our findings, remains to be shown in more extensive studies.

  13. Tunable Semicrystalline Thin Film Cellulose Substrate for High-Resolution, In-Situ AFM Characterization of Enzymatic Cellulose Degradation.

    Science.gov (United States)

    Ganner, Thomas; Roŝker, Stephanie; Eibinger, Manuel; Kraxner, Johanna; Sattelkow, Jürgen; Rattenberger, Johannes; Fitzek, Harald; Chernev, Boril; Grogger, Werner; Nidetzky, Bernd; Plank, Harald

    2015-12-23

    In the field of enzymatic cellulose degradation, fundamental interactions between different enzymes and polymorphic cellulose materials are of essential importance but still not understood in full detail. One technology with the potential of direct visualization of such bioprocesses is atomic force microscopy (AFM) due to its capability of real-time in situ investigations with spatial resolutions down to the molecular scale. To exploit the full capabilities of this technology and unravel fundamental enzyme-cellulose bioprocesses, appropriate cellulose substrates are decisive. In this study, we introduce a semicrystalline-thin-film-cellulose (SCFTC) substrate which fulfills the strong demands on such ideal cellulose substrates by means of (1) tunable polymorphism via variable contents of homogeneously sized cellulose nanocrystals embedded in an amorphous cellulose matrix; (2) nanoflat surface topology for high-resolution and high-speed AFM; and (3) fast, simple, and reproducible fabrication. The study starts with a detailed description of SCTFC preparation protocols including an in-depth material characterization. In the second part, we demonstrate the suitability of SCTFC substrates for enzymatic degradation studies by combined, individual, and sequential exposure to TrCel6A/TrCel7A cellulases (Trichoderma reesei) to visualize synergistic effects down to the nanoscale.

  14. Is the combination of cellulosic polymers and anionic surfactants a good strategy for ensuring physical stability of BCS Class II drug nanosuspensions?

    Science.gov (United States)

    Bilgili, Ecevit; Li, Meng; Afolabi, Afolawemi

    2016-01-01

    Ensuring the physical stability of drug nanosuspensions prepared via wet media milling has been a challenge for pharmaceutical scientists. The aim of this study is to assess the combined use of non-ionic cellulosic polymers and anionic surfactants in stabilizing multiple drug nanosuspensions. Particle size of five drugs, i.e. azodicarbonamide (AZD), fenofibrate (FNB), griseofulvin (GF), ibuprofen (IBU) and phenylbutazone (PB) was reduced separately in an aqueous solution of hydroxypropyl cellulose (HPC) with/without sodium dodecyl sulfate (SDS) via a stirred media mill. Laser diffraction, scanning electron microscopy, thermal analysis, rheometry and electrophoresis were used to evaluate the breakage kinetics, storage stability, electrostatic repulsion and stabilizer adsorption. Without SDS, drug particles exhibited aggregation to different extents; FNB and GF particles aggregated the most due to low zeta potential and insufficient steric stabilization. Although aggregation in all milled suspensions was reduced due to HPC-SDS combination, FNB and IBU showed notable growth during 7-day storage. It is concluded that the combination of non-ionic cellulosic polymers and anionic surfactants is generally viable for ensuring the physical stability of wet-milled drug nanosuspensions, provided that the surfactant concentration is optimized to mitigate the Ostwald ripening, whereas cellulosic polymers alone may provide stability for some drug suspensions.

  15. Optimization of cellulose acrylate and grafted 4-vinylpyridine and 1-vinylimidazole synthesis

    Directory of Open Access Journals (Sweden)

    Bojanić Vaso

    2010-01-01

    Full Text Available Optimization of cellulose acrylate synthesis by reaction with sodium cellulosate and acryloyl chloride was carried out. Optimal conditions for conducting the synthesis reaction of cellulose acrylate were as follows: the molar ratio of cellulose/potassium-t-butoxide/acryloyl chloride was 1:3:10 and the optimal reaction time was 10 h. On the basis of elemental analysis with optimal conditions for conducting the reaction of cellulose acrylate, the percentage of substitution of glucose units in cellulose Y = 80.7%, and the degree of substitution of cellulose acrylate DS = 2.4 was determined. The grafting reaction of acrylate vinyl monomers onto cellulose in acetonitrile with initiator azoisobutyronitrile (AIBN in a nitrogen atmosphere was performed, by mixing for 5 h at acetonitrile boiling temperature. Radical copolymerization of synthesized cellulose acrylate and 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-2-pyrrolidinone and 9-vinylcarbazole, cellulose-poly-4-vinylpyridine (Cell-PVP, cellulose-poly-1- vinylimidazole (Cell-PVIm and cellulose-poly-1-vinyl-2-pyrrolidinone (Cell-P1V2P and cellulose-poly-9-vinylcarbazole (Cell-P9VK were synthesized. Acrylate cellulose and cellulose grafted copolymers were confirmed by IR spectroscopy, based on elementary analysis and the characteristics of grafted copolymers of cellulose were determined. The mass share of grafted copolymers, X, the relationship of derivative parts/cellulose vinyl group, Z, and the degree of grafting copolymers of cellulose (mass% were determined. In reaction of methyl iodide and cellulose-poly-4-vinylpyridine (Cell-PVP the cellulose-1-methyl-poly-4-vinylpyridine iodide (Cell-1-Me-PVPJ was synthesized. Cellulose acrylate and grafted copolymers were obtained with better thermal, electrochemical and ion-emulation properties for bonding of noble metals Au, Pt, Pd from water solutions. The synthesis optimization of cellulose acrylate was applied as a model for the synthesis of grafted

  16. Preparation and characterization of nanoparticles of carboxymethyl cellulose acetate butyrate containing acyclovir

    Science.gov (United States)

    Vedula, Venkata Bharadwaz; Chopra, Maulick; Joseph, Emil; Mazumder, Sonal

    2016-02-01

    Nanoparticles of carboxymethyl cellulose acetate butyrate complexed with the poorly soluble antiviral drug acyclovir (ACV) were produced by precipitation process and the formulation process and properties of nanoparticles were investigated. Two different particle synthesis methods were explored—a conventional precipitation method and a rapid precipitation in a multi-inlet vortex mixer. The particles were processed by rotavap followed by freeze-drying. Particle diameters as measured by dynamic light scattering were dependent on the synthesis method used. The conventional precipitation method did not show desired particle size distribution, whereas particles prepared by the mixer showed well-defined particle size ~125-450 nm before and after freeze-drying, respectively, with narrow polydispersity indices. Fourier transform infrared spectroscopy showed chemical stability and intactness of entrapped drug in the nanoparticles. Differential scanning calorimetry showed that the drug was in amorphous state in the polymer matrix. ACV drug loading was around 10 wt%. The release studies showed increase in solution concentration of drug from the nanoparticles compared to the as-received crystalline drug.

  17. Green synthesis of monodisperse silver nanoparticles using hydroxy propyl methyl cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chunfa; Zhang, Xianglin, E-mail: hust_zxl@mail.hust.edu.cn; Cai, Hao

    2014-01-15

    Graphical abstract: -- Highlights: • Synthesis of silver nanoparticles using hydroxy propyl methyl cellulose is reported. • HPMC and glucose are used as capping agent and reducing agent respectively. • It is the first time to use HPMC for synthesis of silver nanoparticles. • The small, spherical and well-dispersed particle is observed in the range of 3–17 nm. • The green method can be extended to other noble metals. -- Abstract: A simple and environmentally friendly method for the synthesis of highly stable and small sized silver nanoparticles with narrow distribution from 3 nm to 17 nm is reported. Silver nitrate, hydroxy propyl methyl cellulose (HPMC) and glucose, were used as silver precursor, capping agents and reducing agents respectively. The formation of silver nanoparticles was observed by change of color from colorless to wine red. The silver nanoparticles were characterized by transmission electron microscopy (TEM), UV–visible spectroscopy (UV–vis), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FT-IR). The results demonstrated that the obtained metallic nanoparticles were single crystalline silver nanoparticles capped with HPMC. The effects of the reaction time, reaction temperature and the concentration of silver ion and reducing agents on the particle size were investigated. A possible formation mechanism was proposed. The method may be extended to other noble metal for other technological applications such as additional medicinal, industrial applications.

  18. Biochemical Disincentives to Fertilizing Cellulosic Ethanol Crops

    Science.gov (United States)

    Gallagher, M. E.; Hockaday, W. C.; Snapp, S.; McSwiney, C.; Baldock, J.

    2010-12-01

    Corn grain biofuel crops produce the highest yields when the cropping ecosystem is not nitrogen (N)-limited, achieved by application of fertilizer. There are environmental consequences for excessive fertilizer application to crops, including greenhouse gas emissions, hypoxic “dead zones,” and health problems from N runoff into groundwater. The increase in corn acreage in response to demand for alternative fuels (i.e. ethanol) could exacerbate these problems, and divert food supplies to fuel production. A potential substitute for grain ethanol that could reduce some of these impacts is cellulosic ethanol. Cellulosic ethanol feedstocks include grasses (switchgrass), hardwoods, and crop residues (e.g. corn stover, wheat straw). It has been assumed that these feedstocks will require similar N fertilization rates to grain biofuel crops to maximize yields, but carbohydrate yield versus N application has not previously been monitored. We report the biochemical stocks (carbohydrate, protein, and lignin in Mg ha-1) of a corn ecosystem grown under varying N levels. We measured biochemical yield in Mg ha-1 within the grain, leaf and stem, and reproductive parts of corn plants grown at seven N fertilization rates (0-202 kg N ha-1), to evaluate the quantity and quality of these feedstocks across a N fertilization gradient. The N fertilization rate study was performed at the Kellogg Biological Station-Long Term Ecological Research Site (KBS-LTER) in Michigan. Biochemical stocks were measured using 13C nuclear magnetic resonance spectroscopy (NMR), combined with a molecular mixing model (Baldock et al. 2004). Carbohydrate and lignin are the main biochemicals of interest in ethanol production since carbohydrate is the ethanol feedstock, and lignin hinders the carbohydrate to ethanol conversion process. We show that corn residue carbohydrate yields respond only weakly to N fertilization compared to grain. Grain carbohydrate yields plateau in response to fertilization at

  19. Discrimination between naphthacene and triphenylene using cellulose tris(4-methylbenzoate) and cellulose tribenzoate: A computational study.

    Science.gov (United States)

    Murakami, Yusuke; Shibata, Tohru; Ueda, Kazuyoshi

    2017-02-01

    The mechanisms of naphthacene and triphenylene discrimination using commercially available cellulose tris(4-methylbenzoate) (CMB) and cellulose tribenzoate (CB) chiral stationary phases were investigated using molecular mechanics calculations. Naphthacene and triphenylene could be separated by liquid chromatography on CMB and CB, with triphenylene being eluted earlier than naphthacene on both phases. However, the corresponding separation factor is much larger for CMB than for CB. The docking of these polycyclic aromatic hydrocarbons to the above polymers suggested that the most important sites of CMB and CB for interacting with these hydrocarbons are located at equivalent positions, featuring a space surrounded by main chain glucose units and benzoyl side chains. The difference of hydrocarbon stabilization energies with CMB and CB agreed well with the observed chromatographic separation factors.

  20. Dental glass ionomer cement reinforced by cellulose microfibers and cellulose nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rafael M. [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Pereira, Fabiano V., E-mail: fabianovp@ufmg.br [Departamento de Química, Universidade Federal de Minas Gerais, UFMG, Belo Horizonte CEP: 31270-901, MG (Brazil); Mota, Felipe A.P. [Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Watanabe, Evandro [Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirão Preto, USP, Ribeirão Preto CEP: 14040-904, SP (Brazil); Soares, Suelleng M.C.S. [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Santos, Maria Helena [Departamento de Odontologia, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil); Centro Avançado de Avaliação e Desenvolvimento de Biomateriais, BioMat, Universidade Federal do Vale do Jequitinhonha e Mucuri, UFVJM, Diamantina CEP: 39100-000, MG (Brazil)

    2016-01-01

    The aim of this work was to evaluate if the addition of cellulose microfibers (CmF) or cellulose nanocrystals (CNC) would improve the mechanical properties of a commercial dental glass ionomer cement (GIC). Different amounts of CmF and CNC were previously prepared and then added to reinforce the GIC matrix while it was being manipulated. Test specimens with various concentrations of CmF or CNC in their total masses were fabricated and submitted to mechanical tests (to evaluate their compressive and diametral tensile strength, modulus, surface microhardness and wear resistance) and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The incorporation of CmF in the GIC matrix did not greatly improve the mechanical properties of GIC. However, the addition of a small amount of CNC in the GIC led to significant improvements in all of the mechanical properties evaluated: compressive strength (increased up to 110% compared with the control group), elastic modulus increased by 161%, diametral tensile strength increased by 53%, and the mass loss decreased from 10.95 to 3.87%. Because the composites presented a considerable increase in mechanical properties, the modification of the conventional GIC with CNC can represent a new and promising dental restorative material. - Highlights: • Cellulose microfibers (CmF) and cellulose nanocrystals (CNC) were prepared. • The CmF and CNC were incorporated in commercial dental glass ionomer cement (GIC). • Small amount of CNC improved significantly all the mechanical properties evaluated. • Modified GIC with CNC can represent a new and promising dental restorative material.

  1. Removing Cd2+ by Composite Adsorbent Nano-Fe3O4/Bacterial Cellulose

    Institute of Scientific and Technical Information of China (English)

    LU Min; GUAN Xiao-hui; WEI De-zhou

    2011-01-01

    A new composite adsorbent,nano-Fe3O4/bacterial cellulose(BC),was prepared through blending method.The process of adsorbing Cd2+ including its isotherm and kinetics measured was studied.The results show that the adsorption efficiency is improved because of huge surface area and surface coordination of nano-Fe3O4 particles.Its adsorption capacity is 27.97 mg/g and the maximum of Cd2+ removal is 74%.The adsorption kinetics can be described by pseudo-second rate model and the adsorption equilibrium by Langmuir type.The superparamagnetism of nano-Fe3O4 particles can help to solve the difficult separation of single BC adsorbent and lead to the quick separation of composite adsorbent from the liquid if a magnetic field was applied.Cd2+ can be desorbed effectively by EDTA and HCl from the composite adsorbent,which can make it be reused.

  2. Nanocrystalline cellulose extracted from pine wood and corncob.

    Science.gov (United States)

    Ditzel, Fernanda I; Prestes, Eduardo; Carvalho, Benjamim M; Demiate, Ivo M; Pinheiro, Luís A

    2017-02-10

    The extraction of nanocrystalline cellulose from agro-residues is an interesting alternative to recover these materials. In the present study, nanocrystalline cellulose was extracted from pine wood and corncob. In addition, microcrystalline cellulose was used as a reference to compare results. Initially, the lignocellulosic residues were submitted to delignification pre-treatments. At the end of the process, the bleached fibre was submitted to acid hydrolysis. Additionally, microparticles were obtained from the spray-drying of the nanocrystalline cellulose suspensions. The nanocrystalline cellulose yield for the pine wood was 9.0-% of the value attained for the microcrystalline cellulose. For the corncob, the value was 23.5-%. Therefore, complementary studies are necessary to improve the yield. The spray-dried microparticles showed a crystallinity index of 67.8-% for the pine wood, 70.9-% for the corncob and 79.3-% for the microcrystalline cellulose. These microparticles have great potential for use in the production of polymer composites processed by extrusion.

  3. Smart Cellulose Fibers Coated with Carbon Nanotube Networks

    Directory of Open Access Journals (Sweden)

    Haisong Qi

    2014-11-01

    Full Text Available Smart multi-walled carbon nanotube (MWCNT-coated cellulose fibers with a unique sensing ability were manufactured by a simple dip coating process. The formation of electrically-conducting MWCNT networks on cellulose mono- and multi-filament fiber surfaces was confirmed by electrical resistance measurements and visualized by scanning electron microscopy. The interaction between MWCNT networks and cellulose fiber was investigated by Raman spectroscopy. The piezoresistivity of these fibers for strain sensing was investigated. The MWCNT-coated cellulose fibers exhibited a unique linear strain-dependent electrical resistance change up to 18% strain, with good reversibility and repeatability. In addition, the sensing behavior of these fibers to volatile molecules (including vapors of methanol, ethanol, acetone, chloroform and tetrahydrofuran was investigated. The results revealed a rapid response, high sensitivity and good reproducibility for these chemical vapors. Besides, they showed good selectivity to different vapors. It is suggested that the intrinsic physical and chemical features of cellulose fiber, well-formed MWCNT networks and favorable MWCNT-cellulose interaction caused the unique and excellent sensing ability of the MWCNT-coated cellulose fibers, which have the potential to be used as smart materials.

  4. Enhanced cellulose degradation using cellulase-nanosphere complexes.

    Directory of Open Access Journals (Sweden)

    Craig Blanchette

    Full Text Available Enzyme catalyzed conversion of plant biomass to sugars is an inherently inefficient process, and one of the major factors limiting economical biofuel production. This is due to the physical barrier presented by polymers in plant cell walls, including semi-crystalline cellulose, to soluble enzyme accessibility. In contrast to the enzymes currently used in industry, bacterial cellulosomes organize cellulases and other proteins in a scaffold structure, and are highly efficient in degrading cellulose. To mimic this clustered assembly of enzymes, we conjugated cellulase obtained from Trichoderma viride to polystyrene nanospheres (cellulase:NS and tested the hydrolytic activity of this complex on cellulose substrates from purified and natural sources. Cellulase:NS and free cellulase were equally active on soluble carboxymethyl cellulose (CMC; however, the complexed enzyme displayed a higher affinity in its action on microcrystalline cellulose. Similarly, we found that the cellulase:NS complex was more efficient in degrading natural cellulose structures in the thickened walls of cultured wood cells. These results suggest that nanoparticle-bound enzymes can improve catalytic efficiency on physically intractable substrates. We discuss the potential for further enhancement of cellulose degradation by physically clustering combinations of different glycosyl hydrolase enzymes, and applications for using cellulase:NS complexes in biofuel production.

  5. Biological evaluation of nanosilver incorporated cellulose pulp for hygiene products.

    Science.gov (United States)

    Kavitha Sankar, P C; Ramakrishnan, Reshmi; Rosemary, M J

    2016-04-01

    Cellulose pulp has a visible market share in personal hygiene products such as sanitary napkins and baby diapers. However it offers good surface for growth of microorganisms. Huge amount of research is going on in developing hygiene products that do not initiate microbial growth. The objective of the present work is to produce antibacterial cellulose pulp by depositing silver nanopowder on the cellulose fiber. The silver nanoparticles used were of less than 100 nm in size and were characterised using transmission electron microscopy and X-ray powder diffraction studies. Antibacterial activity of the functionalized cellulose pulp was proved by JIS L 1902 method. The in-vitro cytotoxicity, in-vivo vaginal irritation and intracutaneous reactivity studies were done with silver nanopowder incorporated cellulose pulp for introducing a new value added product to the market. Cytotoxicity evaluation suggested that the silver nanoparticle incorporated cellulose pulp is non-cytotoxic. No irritation and skin sensitization were identified in animals tested with specific extracts prepared from the test material in the in-vivo experiments. The results indicated that the silver nanopowder incorporated cellulose pulp meets the requirements of the standard practices recommended for evaluating the biological reactivity and has good biocompatibility, hence can be classified as a safe hygiene product.

  6. Cellulose based hybrid hydroxylated adducts for polyurethane foams

    Science.gov (United States)

    De Pisapia, Laura; Verdolotti, Letizia; Di Mauro, Eduardo; Di Maio, Ernesto; Lavorgna, Marino; Iannace, Salvatore

    2012-07-01

    Hybrid flexible polyurethane foams (HPU) were synthesized by using a hybrid hydroxilated adduct (HHA) based on renewable resources. In particular the HHA was obtained by dispersing cellulose wastes in colloidal silica at room temperature, pressure and humidity. The colloidal silica was selected for its ability of modifying the cellulose structure, by inducing a certain "destructurization" of the crystalline phase, in order to allow cellulose to react with di-isocyanate for the final synthesis of the polyurethane foam. In fact, cellulose-polysilicate complexes are engaged in the reaction with the isocyanate groups. This study provides evidence of the effects of the colloidal silica on the cellulose structure, namely, a reduction of the microfiber cellulose diameter and the formation of hydrogen bonds between the polysilicate functional groups and the hydroxyl groups of the cellulose, as assessed by IR spectroscopy and solid state NMR. The HHA was added to a conventional polyol in different percentages (between 5 and 20%) to synthesize HPU in presence of catalysts, silicone surfactant and diphenylmethane diisocyanate (MDI). The mixture was expanded in a mold and cured for two hours at room temperature. Thermal analysis, optical microscopy and mechanical tests were performed on the foams. The results highlighted an improvement of thermal stability and a decrease of the cell size with respect neat polyurethane foam. Mechanical tests showed an improvement of the elastic modulus and of the damping properties with increasing HHA amount.

  7. Microbial fuel cells using Cellulomonas spp. with cellulose as fuel.

    Science.gov (United States)

    Takeuchi, Yuya; Khawdas, Wichean; Aso, Yuji; Ohara, Hitomi

    2017-03-01

    Cellulomonas fimi, Cellulomonas biazotea, and Cellulomonas flavigena are cellulose-degrading microorganisms chosen to compare the degradation of cellulose. C. fimi degraded 2.5 g/L of cellulose within 4 days, which was the highest quantity among the three microorganisms. The electric current generation by the microbial fuel cell (MFC) using the cellulose-containing medium with C. fimi was measured over 7 days. The medium in the MFC was sampled every 24 h to quantify the degradation of cellulose, and the results showed that the electric current increased with the degradation of cellulose. The maximum electric power generated by the MFC was 38.7 mW/m(2), and this numeric value was 63% of the electric power generated by an MFC with Shewanella oneidensis MR-1, a well-known current-generating microorganism. Our results showed that C. fimi was an excellent candidate to produce the electric current from cellulose via MFCs.

  8. Performance of cellulose derivatives in deep-fried battered snacks: Oil barrier and crispy properties

    NARCIS (Netherlands)

    Primo-Martín, C.; Sanz, T.; Steringa, D.W.; Salvador, A.; Fiszman, S.M.; Vliet, T. van

    2010-01-01

    The performance of batters containing cellulose derivatives (methyl cellulose (A4M), three hydroxypropylmethyl celluloses (E4M, F4M and K4M) with different degree of hydroxypropyl and/or methyl substitution and carboxymethyl cellulose (CMC)) to produce crispy deep-fried snacks crusts was studied by

  9. Direct fermentation of cellulose to ethanol by a cellulolytic filamentous fungus, monilia sp

    Energy Technology Data Exchange (ETDEWEB)

    Gong, C.S.; Maun, C.M.; Tsao, G.T.

    1981-01-01

    Monilia, isolated from bagasse compost, utilized many polysaccharides (including cellulose) and displayed cellulase and hemicellulase activities. Monilia also fermented glucose, xylose, and cellulosic materials to ethanol. Over 60% of the solid cellulose substrate added to Monilia cultures was converted to ethanol as the major fermentation product. Thus, Monilia is a potential organism for the direct conversion of cellulosic biomass to ethanol.

  10. Comparative Structural and Computational Analysis Supports Eighteen Cellulose Synthases in the Plant Cellulose Synthesis Complex.

    Science.gov (United States)

    Nixon, B Tracy; Mansouri, Katayoun; Singh, Abhishek; Du, Juan; Davis, Jonathan K; Lee, Jung-Goo; Slabaugh, Erin; Vandavasi, Venu Gopal; O'Neill, Hugh; Roberts, Eric M; Roberts, Alison W; Yingling, Yaroslava G; Haigler, Candace H

    2016-06-27

    A six-lobed membrane spanning cellulose synthesis complex (CSC) containing multiple cellulose synthase (CESA) glycosyltransferases mediates cellulose microfibril formation. The number of CESAs in the CSC has been debated for decades in light of changing estimates of the diameter of the smallest microfibril formed from the β-1,4 glucan chains synthesized by one CSC. We obtained more direct evidence through generating improved transmission electron microscopy (TEM) images and image averages of the rosette-type CSC, revealing the frequent triangularity and average cross-sectional area in the plasma membrane of its individual lobes. Trimeric oligomers of two alternative CESA computational models corresponded well with individual lobe geometry. A six-fold assembly of the trimeric computational oligomer had the lowest potential energy per monomer and was consistent with rosette CSC morphology. Negative stain TEM and image averaging showed the triangularity of a recombinant CESA cytosolic domain, consistent with previous modeling of its trimeric nature from small angle scattering (SAXS) data. Six trimeric SAXS models nearly filled the space below an average FF-TEM image of the rosette CSC. In summary, the multifaceted data support a rosette CSC with 18 CESAs that mediates the synthesis of a fundamental microfibril composed of 18 glucan chains.

  11. Cellulose nanowhiskers and nanofibers from biomass for composite applications

    Science.gov (United States)

    Wang, Tao

    2011-12-01

    Biological nanocomposites such as plant cell wall exhibit high mechanical properties at a light weight. The secret of the rigidity and strength of the cell wall lies in its main structural component -- cellulose. Native cellulose exists as highly-ordered microfibrils, which are just a few nanometers wide and have been found to be stiffer than many synthetic fibers. In the quest for sustainable development around the world, using cellulose microfibrils from plant materials as renewable alternatives to conventional reinforcement materials such as glass fibers and carbon fibers is generating particular interest. In this research, by mechanical disintegration and by controlled chemical hydrolysis, both cellulose nanofibers and nanowhiskers were extracted from the cell wall of an agricultural waste, wheat straw. The reinforcement performances of the two nanofillers were then studied and compared using the water-soluble polyvinyl alcohol (PVOH) as a matrix material. It was found that while both of these nanofillers could impart higher stiffness to the polymer, the nanofibers from biomass were more effective in composite reinforcement than the cellulose crystals thanks to their large aspect ratio and their ability to form interconnected network structures through hydrogen bonding. One of the biggest challenges in the development of cellulose nanocomposites is achieving good dispersion. Because of the high density of hydroxyl groups on the surface of cellulose, it remains a difficult task to disperse cellulose nanofibers in many commonly used polymer matrices. The present work addresses this issue by developing a water-based route taking advantage of polymer colloidal suspensions. Combining cellulose nanofibers with one of the most important biopolymers, poly(lactic acid) (PLA), we have prepared nanocomposites with excellent fiber dispersion and improved modulus and strength. The bio-based nanocomposites have a great potential to serve as light-weight structural materials

  12. Influence of Tableting on Enzymatic Activity of Papain along with Determination of Its Percolation Threshold with Microcrystalline Cellulose.

    Science.gov (United States)

    Sharma, Manu; Sharma, Vinay; Majumdar, Dipak K

    2014-01-01

    The binary mixture tablets of papain and microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), carrageenan, tragacanth, and agar were prepared by direct compression. Carrageenan, tragacanth, and agar provided maximum protection to enzyme activity compared to MCC and DCP. However, stability studies indicated highest loss of enzyme activity with carrageenan, tragacanth, and agar. Therefore, compression behaviour of different binary mixtures of papain with MCC at different compaction pressures, that is, 40-280 MPa, was studied according to Heckel equation. The compressibility studies of binary mixtures indicated brittle behavior of papain. The application of percolation theory on the relationship between critical density as a function of enzyme activity and mixture composition revealed the presence of percolation threshold for binary mixture. Papain-MCC mixture composition showed significant percolation threshold at 18.48% (w/w) papain loading. Microcrystalline cellulose provided higher protection during stability study. However, higher concentrations of microcrystalline cellulose, probably as dominant particles, do not protect the enzyme with their plastic deformation. Below the percolation threshold, that is, 18.48% (w/w) papain amount in mixture with plastic excipient, activity loss increases strongly because of higher shearing forces during compaction due to system dominance of plastic particles. This mixture range should therefore be avoided to get robust formulation of papain.

  13. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    Science.gov (United States)

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-05

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption.

  14. The gelation of oil using ethyl cellulose.

    Science.gov (United States)

    Davidovich-Pinhas, M; Barbut, S; Marangoni, A G

    2015-03-06

    The characterization of the thermo-gelation mechanism and properties of ethyl cellulose/canola oil oleogels was performed using rheology and thermal analysis. Thermal analysis detected no evidence for thermal transitions contributed to secondary conformational changes, suggesting a gelation mechanism that does not involve secondary ordered structure formation. Rheological analysis demonstrated a relationship between the polymer molecular weight and the final gel strength, the cross-over behavior as well as the gel point temperature. Increasing polymer molecular weight led to an increase in final gel strength, the modulus at cross-over, and the gel point temperature. Cooling/heating rates affect gel modulus only for the low molecular weight samples. A decrease in gel strength with increasing cooling rate was detected. The cross-over temperature was not affected by the cooling/heating rates. Cooling rate also affected the gelation setting time where slow cooling rates produced a stable gel faster.

  15. 以离子液体为溶剂制备纤维素微球%Cellulose microspheres preparation using ionic liquid as the solvent

    Institute of Scientific and Technical Information of China (English)

    侯祥; 魏立纲; 马英冲; 李坤兰; 王少君; 余加祐

    2011-01-01

    Cellulose microspheres were prepared using the cellulose-ionic liquid (ID solution was prepared by directly dissolving by reversed -phase suspension technique. Effects of the used cellulose type, cellulose content in the solution, disperse phase, agitation speed, temperature on particle size distribution were discussed. In the case of 2% cotton cellulose/IL solution, heat transfer oil as disperse phase, 50:1 of volume ratio of oil and solution, PEG 600 as disperse agent, 500 r/min of the agitation speed and 80 °C, 55% cellulose microspheres with particle size 0.45 to 0.20 mm can be obtained.%将天然纤维素溶于离子液体中,制成纤维素/离子液体溶液,并以纤维素/离子液体溶液为原料采用悬浮聚合法制备了纤维素微球.讨论了纤维素种类和质量分数、纤维素/离子液体溶液与导热油体积比、搅拌速度和制备温度对纤维素微球粒径分布的影响.结果表明,质量分数为2%的棉纤维素/离子液体溶液,以导热油为分散相,V(纤维素/离子液体溶液):V(导热油)=1:50,聚乙二醇(相对分子质量600)作为分散剂,搅拌速度为500 r/min,制备温度为80℃,可制得粒径分布在0.45~0.20 mm占55%以上的纤维素微球.

  16. Impact of cellulose ethers on the cement paste microstructure

    OpenAIRE

    Pourchez, Jérémie; Grosseau, Philippe; Rouèche-Pourchez, Emilie; Debayle, Johan; Pinoli, Jean-Charles; Maire, Eric; Boller, Elodie; Parra-Denis, Estelle

    2007-01-01

    ISBN = 3-87264-022-4 7 pages; International audience; Complementary investigation tools (2D and 3D observations by optical microscopy and fast X-ray microtomography and then image analysis) were developed in order to examine the effects of cellulose ethers on the cement paste microstructure. The obtained results show that the presence of cellulose ether may induce an increase of both 50-250 µm-diameter air voids. The chemistry of the cellulose ethers appears as a main controlling factor of th...

  17. Sustainable green composites of thermoplastic starch and cellulose fibers

    Directory of Open Access Journals (Sweden)

    Amnuay Wattanakornsiri

    2014-04-01

    Full Text Available Green composites have gained renewed interest as environmental friendly materials and as biodegradable renewable resources for a sustainable development. This review provides an overview of recent advances in green composites based on thermoplastic starch (TPS and cellulose fibers. It includes information about compositions, preparations, and properties of starch, cellulose fibers, TPS, and green composites based on TPS and cellulose fibers. Introduction and production of these recyclable composites into the material market would be important for environmental sustainability as their use can decrease the volume of petroleum derived plastic waste dumps. Green composites are comparable cheap and abundant, but further research and development is needed for a broader utilization.

  18. Fabrication of Piezoelectric Cellulose Paper and Audio Application

    Institute of Scientific and Technical Information of China (English)

    Jung-Hwan Kim; Sungryul Yun; Joo-Hyung Kim; Jaehwan Kim

    2009-01-01

    We report the fabrication process of piezoelectric cellulose paper and the enhancement method of its piezoelectric property.Stretching method with different wet-drawing ratios was introduced to increase the piezoelectric property of cellulose paper during regeneration process. It is observed that the Young's modulus and the piezoelectric charge constants are very dependent on the drawing ratio and the direction of nanofibrils of piezoelectric paper. Using the enhanced piezoelectric property, we prove that the flexible regenerated piezoelectric cellulose can be applied to the potential acoustic applications such as thin piezoelectric paper speaker.

  19. Preliminary Research on Structure and Properties of Nano-cellulose

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structure of bacterial cellulose (BC) produced by Acetobacter xylinum NUST4 (A.xylinum NUST4) under static (SBC) and shake culture condition (ABC) was studied by means of transmission electron microscopic (TEM), X-ray diffraction (XRD) and Fourier transform-infrared spectrum (FT-IR). It was revealed that BC is Ⅰ crystal cellulose and the proportion of cellulose Ⅰα exceeds 80% and BC diameter is 10-80 nm.Mechanical properties and water absorption capacity were also determined. These properties could result from crystalline and nanometer structure of BC.

  20. GRAFTING OF HUMIC ACID ONTO COTTON CELLULOSE (Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    CHEN Qi; ZHANG Dehe

    1988-01-01

    Cotton cellulose reacted with epichlorohydrin under the catalytic action of HClO4 and H2O to form 3-chloro-2-hydroxypropyl ether with a substitution degree of 0.61. The chlorine-containing product was treated with aliphatic diamines (ethylenediamine, propylenediamine, etc.) to produce nitrogen-containing cellulose which further reacted with humic acid to give black fiberous graft cellulose. This product contains 27-35%humic acid, 0.90 meq/g acidic groups, possesses 0.49 meq/g Cu2 +-complexing capacity and good mechanical strength, and can be used under pH12.

  1. Particle therapy

    Energy Technology Data Exchange (ETDEWEB)

    Raju, M.R.

    1993-09-01

    Particle therapy has a long history. The experimentation with particles for their therapeutic application got started soon after they were produced in the laboratory. Physicists played a major role in proposing the potential applications in radiotherapy as well as in the development of particle therapy. A brief review of the current status of particle radiotherapy with some historical perspective is presented and specific contributions made by physicists will be pointed out wherever appropriate. The rationale of using particles in cancer treatment is to reduce the treatment volume to the target volume by using precise dose distributions in three dimensions by using particles such as protons and to improve the differential effects on tumors compared to normal tissues by using high-LET radiations such as neutrons. Pions and heavy ions combine the above two characteristics.

  2. Ultrafine particles

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Weschler, Charles J.; Wierzbicka, Aneta;

    2013-01-01

    Particle number (PN) concentrations (10-300 nm in size) were continuously measured over a period of ∼45 h in 56 residences of nonsmokers in Copenhagen, Denmark. The highest concentrations were measured when occupants were present and awake (geometric mean, GM: 22.3 × 103 cm-3), the lowest when...... the homes were vacant (GM: 6.1 × 103 cm-3) or the occupants were asleep (GM: 5.1 × 103 cm-3). Diary entries regarding occupancy and particle related activities were used to identify source events and apportion the daily integrated exposure among sources. Source events clearly resulted in increased PN...... concentrations and decreased average particle diameter. For a given event, elevated particle concentrations persisted for several hours after the emission of fresh particles ceased. The residential daily integrated PN exposure in the 56 homes ranged between 37 × 103 and 6.0 × 106 particles per cm3·h/day (GM: 3...

  3. The mathematical model of dye diffusion and adsorption on modified cellulose with triazine derivatives containing cationic and anionic groups

    Science.gov (United States)

    Xie, K.; Hou, A.; Chen, Y.

    2008-02-01

    Cellulose fabric is chemically modified with the compounds containing cationic and anionic groups. The molecular chains of modified cellulose have both cationic and anionic groups. Dye diffusion properties on modified cellulose are discussed. The dye adsorption and diffusion on modified cellulose are higher than those on unmodified cellulose. The diffusion properties of dyes at different temperature are discussed. Compared with unmodified cellulose, the diffusion processing of dyes in the modified cotton cellulose shows significant change.

  4. Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants.

    Science.gov (United States)

    Li, Shundai; Bashline, Logan; Zheng, Yunzhen; Xin, Xiaoran; Huang, Shixin; Kong, Zhaosheng; Kim, Seong H; Cosgrove, Daniel J; Gu, Ying

    2016-10-04

    Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.

  5. Directional Freezing of Nanocellulose Dispersions Aligns the Rod-Like Particles and Produces Low-Density and Robust Particle Networks.

    Science.gov (United States)

    Munier, Pierre; Gordeyeva, Korneliya; Bergström, Lennart; Fall, Andreas B

    2016-05-01

    We show that unidirectional freezing of nanocellulose dispersions produces cellular foams with high alignment of the rod-like nanoparticles in the freezing direction. Quantification of the alignment in the long direction of the tubular pores with X-ray diffraction shows high orientation of cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) at particle concentrations above 0.2 wt % (CNC) and 0.08 wt % (CNF). Aggregation of CNF by pH decrease or addition of salt significantly reduces the particle orientation; in contrast, exceeding the concentration where particles gel by mobility constraints had a relatively small effect on the orientation. The dense nanocellulose network formed by directional freezing was sufficiently strong to resist melting. The formed hydrogels were birefringent and displayed anisotropic laser diffraction patterns, suggesting preserved nanocellulose alignment and cellular structure. Nondirectional freezing of the hydrogels followed by sublimation generates foams with a pore structure and nanocellulose alignment resembling the structure of the initial directional freezing.

  6. Particle Physics

    CERN Document Server

    Martin, B R

    2008-01-01

    An essential introduction to particle physics, with coverage ranging from the basics through to the very latest developments, in an accessible and carefully structured text. Particle Physics: Third Edition is a revision of a highly regarded introduction to particle physics. In its two previous editions this book has proved to be an accessible and balanced introduction to modern particle physics, suitable for those students needed a more comprehensive introduction to the subject than provided by the 'compendium' style physics books. In the Third Edition the standard mod

  7. The Effect of Particle Properties on Hot Particle Spot Fire Ignition

    Science.gov (United States)

    Zak, Casey David

    The ignition of natural combustible material by hot metal particles is an important fire ignition pathway by which wildland and wildland-urban-interface spot fires are started. There are numerous cases reported of wild fires started by clashing power-lines or from sparks generated by machines or engines. Similarly there are many cases reported of fires caused by grinding, welding and cutting sparks. Up to this point, research on hot particle spot fire ignition has largely focused on particle generation and transport. A small number of studies have examined what occurs after a hot particle contacts a natural fuel bed, but until recently the process remained poorly understood. This work describes an investigation of the effect of particle size, temperature and thermal properties on the ability of hot particles to cause flaming ignition of cellulosic fuel beds. Both experimental and theoretical approaches are used, with a focus on understanding the physics underlying the ignition process. For the experimental study, spheres of stainless steel, aluminum, brass and copper are heated in a tube furnace and dropped onto a powdered cellulose fuel bed; the occurrence of flaming ignition or lack thereof is visually observed and recorded. This procedure is repeated a large number of times for each metal type, varying particle diameter from 2 to 11 mm and particle temperature between 575 and 1100°C. The results of these experiments are statistically analyzed to find approximate ignition boundaries and identify boundary trends with respect to the particle parameters of interest. Schlieren images recorded during the ignition experiments are also used to more accurately describe the ignition process. Based on these images, a simple theoretical model of hot particle spot fire ignition is developed and used to explore the experimental trends further. The model under-predicts the minimum ignition temperatures required for small spheres, but agrees qualitatively with the experimental

  8. The influence of the moisture content of microcrystalline cellulose on the coating process in a fluidized bed

    Directory of Open Access Journals (Sweden)

    Silva O. S.

    2004-01-01

    Full Text Available The objective of this work was to study the coating of microcrystalline cellulose with a polymeric suspension in a fluidized bed. The coating operation was carried out using a fluidized bed with top spraying by a double-fluid nozzle. The fluidized bed consists of a cylindrical column made of plexiglass with a height of 0.6 m and an inner diameter of 0.14 m. The polymeric coating suspension was formulated using Eudragit® as the basic component. As the quality of the coating product is greatly affected by the spraying characteristics, the influence of the flow rate of the coating suspension and the moisture content of the particles on the agglomeration index and efficiency of the process of coating microcrystalline cellulose was analyzed.

  9. The Influence of Clay on the Rate of Decay of Amino Acid Metabolites Synthesized in Soils during Decomposition of Cellulose

    DEFF Research Database (Denmark)

    Sørensen, Lasse Holst

    1975-01-01

    14C-labelled cellulose was added to seven different soils containing silt + clay (particles .... The amounts of labelled amino acid C in the soils were proportional to their content of silt + clay. After 30 days of incubation labelled amino acid C remaining in the soil with the lowest content of silt + clay constituted 6 per cent of the carbon added in cellulose, as compared with 18 per cent in the soil...... with the highest content of silt + clay. These values had decreased to 5 and 13 per cent respectively after 2 years of incubation. The order between the soils in the content of labelled amino acid C established during the first month of incubation, was thus roughly maintained throughout the period of incubation...

  10. Biomimetic Mineralization on a Macroporous Cellulose-Based Matrix for Bone Regeneration

    OpenAIRE

    2013-01-01

    The aim of this study is to investigate the biomimetic mineralization on a cellulose-based porous matrix with an improved biological profile. The cellulose matrix was precalcified using three methods: (i) cellulose samples were treated with a solution of calcium chloride and diammonium hydrogen phosphate; (ii) the carboxymethylated cellulose matrix was stored in a saturated calcium hydroxide solution; (iii) the cellulose matrix was mixed with a calcium silicate solution in order to introduce ...

  11. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

    Institute of Scientific and Technical Information of China (English)

    Peng-fei Gao; Dai-di Fan; Pei Ma; Yan-e Luo; Xiao-xuan Ma; Chen-hui Zhu; Jun-feng Hui

    2009-01-01

    Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulosc Congo red coltnre medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplished for each of the five. The strongest of the five in CMCA and FPA was applied to the production of cellulose bioethanol by separate hydrolysis and fermentation(SHF) and simultaneous saccharification and fermentation(SSF) respectively.

  12. Simple approach to reinforce hydrogels with cellulose nanocrystals

    Science.gov (United States)

    Yang, Jun; Han, Chun-Rui; Xu, Feng; Sun, Run-Cang

    2014-05-01

    The physical crosslinking of colloidal nanoparticles via dynamic and directional non-covalent interactions has led to significant advances in composite hydrogels. In this paper, we report a simple approach to fabricate tough, stretchable and hysteretic isotropic nanocomposite hydrogels, where rod-like cellulose nanocrystals (CNCs) are encapsulated by flexible polymer chains of poly(N,N-dimethylacrylamide) (PDMA). The CNC-PDMA colloidal clusters build a homogeneously cross-linked network and lead to significant reinforcing effect of the composites. Hierarchically structured CNC-PDMA clusters, from isolated particles to an interpenetrated network, are observed by transmission electron microscopy measurements. Dynamic shear oscillation measurements are applied to demystify the differences in network rheological behaviors, which were compared with network behaviors of chemically cross-linked PDMA counterparts. Tensile tests indicate that the hybrid hydrogels possess higher mechanical properties and a more efficient energy dissipation mechanism. In particular, with only 0.8 wt% of CNC loading, a 4.8-fold increase in Young's modulus, 9.2-fold increase in tensile strength, and 5.8-fold increase in fracture strain are achieved, which is ascribed to a combination of CNC reinforcement in the soft matrix and CNC-PDMA colloidal cluster conformational rearrangement under stretching. Physical interactions within networks serve as reversible sacrificial bonds that dissociate upon deformation, exhibiting large hysteresis as an energy dissipation mechanism via cluster mobility. This result contrasts with the case of chemically cross-linked PDMA counterparts where the stress relaxation is slow due to the permanent cross-links and low resistance against crack propagation within the covalent network.The physical crosslinking of colloidal nanoparticles via dynamic and directional non-covalent interactions has led to significant advances in composite hydrogels. In this paper, we report

  13. Coaggregation of mineral filler particles and starch granules as a basis for improving filler-fiber interaction in paper production.

    Science.gov (United States)

    Li, Ting; Fan, Jun; Chen, Wensen; Shu, Jiayan; Qian, Xueren; Wei, Haifeng; Wang, Qingwen; Shen, Jing

    2016-09-20

    The sustainable, efficient use of renewable bio-based additives in the production of various materials fits well into the concept of sustainability. Here, the concept of coaggregation of mineral filler particles and starch granules for improving filler-fiber interaction in paper-based cellulosic networks is presented. Coaggregation of precipitated calcium carbonate filler particles and uncooked, unmodified corn starch granules by cationic polyacrylamide (a cationic high molecular weight polymer flocculant) in combination with bentonite (an anionic microparticle) prior to addition to cellulosic fiber slurry delivered enhanced filler bondability with cellulosic fibers. For instance, under the conditions studied, preaggregation resulted in an increase in filler bondability factor from 9.24 to 15.21 at starch dosage of 1% (on the basis of the dry weight of papermaking stock). The swelling and gelatinization of the starch granules in starch-filler preaggregates or hybrids enabled the "bridging" of the gaps in cellulosic networks, leading to structural consolidation and strength enhancement.

  14. 6-Deoxy-6-aminoethyleneamino cellulose: synthesis and study of hemocompatibility.

    Science.gov (United States)

    Zieger, Michael; Wurlitzer, Michael; Wiegand, Cornelia; Reddersen, Kirsten; Finger, Susanne; Elsner, Peter; Laudeley, Peggy; Liebert, Tim; Heinze, Thomas; Hipler, Uta-Christina

    2015-01-01

    Hemocompatibility of aqueous solutions of antimicrobial 6-deoxy-6-aminoethyleneamino (AEA) cellulose with different degrees of substitution (DS, 0.54-0.92) was investigated in vitro. The AEA cellulose derivatives were synthesized by tosylation of cellulose and subsequent nucleophilic substitution with 1,2-diaminoethane. The structure was confirmed by elemental analysis as well as by FTIR and NMR spectroscopies. Markers for coagulation (thrombin generation, aPTT, PT, blood clotting, thrombocyte activation) and membrane integrity (hemolysis) were measured in human whole blood, human platelet-rich plasma, human pooled plasma, and erythrocytes suspension. AEA cellulose with a low DS of 0.54 showed the highest hemocompatibility in vitro, suggesting the possibility of biomedical applications.

  15. Sustainable commercial nanocrystalline cellulose manufacturing process with acid recycling.

    Science.gov (United States)

    Sarma, Saurabh Jyoti; Ayadi, Mariem; Brar, Satinder Kaur; Berry, Richard

    2017-01-20

    Nanocrystalline cellulose (NCC) is a biomaterial having potential applications in a wide range of industries. It is industrially produced by concentrated acid hydrolysis of cellulosic materials. In this process, the sulfuric acid rich liquor can be concentrated and reused. However, removal of sugar monomers and oligomers is necessary for such recycling. Membrane and ion exchange technology can be employed to remove sugars; however, such technologies are not efficient in meeting the quality required to recycle the acid solution. As a part of the present study, activated carbon (AC) has been evaluated as an adsorbent for sugar removal from the acidic solution generated during commercial nanocrystalline cellulose manufacturing process. Almost complete removal of sugar can be achieved by this approach. The maximum sugar removal observed during this study was 3.4g/g of AC. Based on this finding, a sustainable method has been proposed for commercial nanocrystalline cellulose manufacturing.

  16. Photooxidation of cellulose nitrate: new insights into degradation mechanisms.

    Science.gov (United States)

    Berthumeyrie, Sebastien; Collin, Steeve; Bussiere, Pierre-Olivier; Therias, Sandrine

    2014-05-15

    Cellulose nitrate (or nitrocellulose) has received considerable interest due to its uses in various applications, such as paints, photographic films and propellants. However, it is considered as one of the primary pollutants in the energetic material industries because it can be degraded to form polluting chemical species. In this work, the UV light degradation of cellulose nitrate films was studied under conditions of artificially accelerated photooxidation. To eliminate the reactivity of nitro groups, the degradation of ethylcellulose was also investigated. Infrared spectroscopy analyses of the chemical modifications caused by the photooxidation of cellulose nitrate films and the resulting formation of volatile products revealed the occurrence of de-nitration and the formation of oxidation photoproducts exhibiting lactone and anhydride functions. The impact of these chemical modifications on the mechanical and thermal properties of cellulose nitrate films includes embrittlement and lower temperatures of ignition when used as a propellant.

  17. Natural Composites: Cellulose Fibres and the related Performance of Composites

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2014-01-01

    Biobased materials are becoming of increasing interest as potential structural materials for the future. A useful concept in this context is the fibre reinforcement of materials by stiff and strong fibres. The biobased resources can contribute with cellulose fibres and biopolymers. This offers...... the potential for stiff and strong biocomposite materials, but these have some limitations and obstacles to full performance. The focus will be on the ultra-structure, and the strength and stiffness of cellulose fibres, on the (unavoidable) defects causing large reductions in strength and moderate reductions...... in stiffness, on the packing ability of cellulose fibres and the related maximum fibre volume fraction in composites, on the moisture sorption of cellulose fibres and the related mass increase and (large) hygral strains induced, and on the mechanical performance of composites....

  18. Decomposition of Cellulose by Continuous Near-Critical Water Reactions

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A pilot-scale apparatus for continuous supercritical and near-critical water reaction was set up. A high- pressure slurry supplying system was developed to feed the solid material-water slurries. The apparatus features temperature up to 600℃, pressure up to 40MPa, residence time from 24s to 15min, maximum amount of slurry supply of 2.4 L.h-1, maximum solid content of slurry up to 10%(by mass) for cellulose from Merck, and resistance to corrosion. Long-time runs of decomposition of cellulose were carried out and steady runs were confirmed. Kinetics of cellulose decomposition was studied. The apparent activation energy evaluated was 147kJ·mol-1. In addition, a new three-step pathway for cellulose hydrolysis was proposed. The derived kinetic equation is in good agreement with the experimental data.

  19. Synthesis and properties of fluorescent cotton cellulose labeled with norfloxacin

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    To expand the application of cellulose in the field of fluorescence techniques, the cotton cellulose was labeled with norfloxacin (Cell-NF) via a three-step reaction, involving alkali treatment, epoxy activation, and opening of the epoxy rings with norfloxacin molecules. And the coordination complexes of Cell-NF with rare earth ions terbium (Cell-NF-Tb) and europium (Cell-NF-Eu) were obtained. The products were detected by IR, TG, XPS, UV and fluorescence spectra. Results showed that the norfloxacin content of the labeled cellulose was about 6.73 w‰ and the start temperature of decomposition of the Cell-NF was raised by 40°C compared with the stock cotton cellulose. When excited at 340 nm, the Cell-NF, Cell-NF-Tb, and Cell-NF-Eu in the solid state could emit violet (430 nm), green (549 nm) and red (620 nm) light, respectively.

  20. Synthesis and characterization of novel cellulose ether sulfates.

    Science.gov (United States)

    Rohowsky, Juta; Heise, Katja; Fischer, Steffen; Hettrich, Kay

    2016-05-20

    The synthesis and characterization of novel cellulose sulfate derivatives was reported. Various cellulose ethers were prepared in a homogeneous reaction with common sulfating agents. The received product possess different properties in dependence on the reaction conditions like sulfating agent, solvent, reaction time and reaction temperature. The cellulose ether sulfates are all soluble in water, they rheological behavior could be determined by viscosity measurements and the determination of the sulfur content by elemental analysis lead to a resulting degree of substitution ascribed to sulfate groups (DSSul) of the product. A wide range of products from DSSul 0.1 to DSSul 2.7 will be obtained. Furthermore the cellulose sulfate ethers could be characterized by Raman spectroscopy.

  1. Study of Cellulose Interaction with Concentrated Solutions of Sulfuric Acid

    OpenAIRE

    Michael Ioelovich

    2012-01-01

    The effect of the concentration of sulfuric acid (SA) and temperature on structure and properties of cellulose (MCC) had been studied. Investigations showed that solubility of the initial sample at the room temperature increased gradually in the range of the acid concentration from 50 to 60 wt.% SA. When SA concentration reached 65 wt.%, then MCC sample dissolved completely. Cellulose regenerated from 65 wt.% SA had an amorphized structure and was characterized by high enzymatic digestibility...

  2. Preparation and characterization of gelatin scaffold containing microorganism fermented cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Youn Mook; Gwon, Hui Jeong; Park, Jong Seok; Nho, Young Chang; Lee, Byeong Heon [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kim, Mi Yeong; Lee, Jong Dae; Song, Sung Gi [Quegenbiotech, Co., Incheon (Korea, Republic of)

    2010-12-15

    Cellulose, chitin, chitosan and hyaluronic acid are well known as polysaccharides. These polysaccharides have many effects on cell growth and differentiation. Cell activation increases with increasing the polysaccharides concentration. In this study, gelatin scaffold containing microorganism fermented cellulose, citrus gel were prepared by using irradiation technique. Physical properties of the scaffolds were investigated as a function of the concentrations of gelatin and citrus gel and the cell attachment, cell morphology and inflammation of the scaffolds also were characterized for regeneration of skin tissue.

  3. CHARACTERIZATION OF CAPTOPRIL-ETHYL CELLULOSE MICROSPHERES BY THERMAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    RakeshGupta

    2010-06-01

    Full Text Available The objective of the present study was to study the physical characterization of Captopril-ethyl cellulose microspheres by thermal analysis such as Differential Scanning Calorimetry (DSC, Differential thermal analysis (DTA and Thermo gravimetry (TG. Drug polymer interaction can directly affect the dosage form stability, drug encapsulation into polymers and dissolution patterns. In this study thermal analysis has been carried out for the physical mixtures and microspheres of captopril and ethyl cellulose prepared by solvent evaporation method.

  4. Cellulose digestion in heterotmes indicola, Wasmann and Coptotermes HIEMI Wasmann

    Directory of Open Access Journals (Sweden)

    J. N. Misra

    1960-07-01

    Full Text Available High activities of cellulose and cellobiase have been found in the gut extracts of the worker caste of two species of Heterotermes indicola, Wasmann and Coptotermes heimi, Wasmann. The properties of the two enzymes from H. Indicola have been investigated. It has been found that the soldier caste of these termites is capable of splitting cellobiose while incapable of breaking down cellulose into simpler sugars.

  5. Energy consumption in the production of cellulose and paper

    Energy Technology Data Exchange (ETDEWEB)

    Kubelka, V.

    1979-01-01

    The specific consumption of energy in the cellulose and paper industry of Czechoslovakia is 20% higher than in Austria and the Federal Republic of Germany. For the last 20 years, the specific consumption of fuel decreased by 29% in the Austrian cellulose and paper industry, while the consumption of electricity increased by 16%. The possibility for decreasing the specific consumption of energy in Czechoslovakia by burning by-products, heat recovery, equipment modernization, etc. are examined.

  6. Structure and Property of Silk Fibroin / Cellulose Blend Film

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-qiang; XING Tie-ling

    2004-01-01

    Silk fibroin/cellulose blend films were prepared using N-methylmorpholine -N-oxide (NMMO) as solvent. The effects of different proportions and solid contents on properties of blend films were discussed. The mechanical properties showed that the blend films had preferable moisture permeability and a high strength. The structures of the blend films were investigated by infrared spectrum and X-ray diffraction. The results indicated the occurrence of hydrogen bonds between hydroxyl groups of cellulose and amido groups of fibroin.

  7. Breakdown of hierarchical architecture in cellulose during dilute acid pretreatments

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan [Northeastern Univ., Boston, MA (United States); Inouye, Hideyo [Northeastern Univ., Boston, MA (United States); Yang, Lin [Brookhaven National Lab. (BNL), Upton, NY (United States); Himmel, Michael E. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tucker, Melvin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Makowski, Lee [Northeastern Univ., Boston, MA (United States)

    2015-02-28

    Cellulose can work as a feedstock for sustainable bioenergy because of its global abundance. Pretreatment of biomass has significant influence on the chemical availability of cellulose locked in recalcitrant microfibrils. Optimizing pretreatment depends on an understanding of its impact on the microscale and nanoscale molecular architecture. X-ray scattering experiments have been performed on native and pre-treated maize stover and models of cellulose architecture have been derived from these data. Ultra small-angle, very small-angle and small-angle X-ray scattering (USAXS, VSAXS and SAXS) probe three different levels of architectural scale. USAXS and SAXS have been used to study cellulose at two distinct length scales, modeling the fibrils as ~30 Å diameter rods packed into ~0.14 μm diameter bundles. VSAXS is sensitive to structural features at length scales between these two extremes. Detailed analysis of diffraction patterns from untreated and pretreated maize using cylindrical Guinier plots and the derivatives of these plots reveals the presence of substructures within the ~0.14 μm diameter bundles that correspond to grouping of cellulose approximately 30 nm in diameter. These sub-structures are resilient to dilute acid pretreatments but are sensitive to pretreatment when iron sulfate is added. Our results provide evidence of the hierarchical arrangement of cellulose at three length scales and the evolution of these arrangements during pre-treatments.

  8. Functionalization of Cellulose Nanocrystals in Choline Lactate Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Sarah Montes

    2016-06-01

    Full Text Available Cellulose nanocrystals (CNCs are valuable nanomaterials obtained from renewable resources. Their properties make them suitable for a wide range of applications, including polymer reinforcement. However, due to their highly hydrophilic character, it is necessary to modify their surface with non-polar functional groups before their incorporation into a hydrophobic polymer matrix. In this work, cellulose nanocrystals were modified using a silane coupling agent and choline lactate, an ionic liquid derived from renewable resources, as a reaction medium. Modified cellulose nanocrystals were characterized by infrared spectroscopy, showing new peaks associated to the modification performed. X-ray diffraction was used to analyze the crystalline structure of functionalized cellulose nanocrystals and to optimize the amount of silane for functionalization. Poly(lactic acid (PLA nanocomposites containing 1 wt % of functionalized cellulose nanocrystals were prepared. They were characterized by field-emission scanning electron microscopy (FE-SEM and mechanical tests. The use of choline lactate as reaction media has been shown to be an alternative method for the dispersion and silanization of the cellulose nanocrystals without the addition of an external catalyst.

  9. Effects of cellulose whiskers on properties of soy protein thermoplastics.

    Science.gov (United States)

    Wang, Yixiang; Cao, Xiaodong; Zhang, Lina

    2006-07-14

    Environmentally-friendly SPI/cellulose whisker composites were successfully prepared using a colloidal suspension of cellulose whiskers, to reinforce soy protein isolate (SPI) plastics. The cellulose whiskers, having an average length of 1.2 microm and diameter of 90 nm, respectively, were prepared from cotton linter pulp by hydrolyzing with sulfuric acid aqueous solution. The effects of the whisker content on the morphology and properties of the glycerol-plasticized SPI composites were investigated by scanning electron microscopy, dynamic mechanical thermal analysis, differential scanning calorimetry, ultraviolet-visible spectroscopy, water-resistivity testing and tensile testing. The results indicated that, with the addition of 0 to 30 wt.-% of cellulose whiskers, strong interactions occurred both between the whiskers and between the filler and the SPI matrix, reinforcing the composites and preserving their biodegradability. Both the tensile strength and Young's modulus of the SPI/cellulose whisker composites increased from 5.8 to 8.1 MPa and from 44.7 to 133.2 MPa, respectively, at a relative humidity of 43%, following an increase of the whisker content from 0 to 30 wt.-%. Furthermore, the incorporation of the cellulose whiskers into the SPI matrix led to an improvement in the water resistance for the SPI-based composites.

  10. Mechanics of Cellulose Synthase Complexes in Living Plant Cells

    Science.gov (United States)

    Zehfroosh, Nina; Liu, Derui; Ramos, Kieran P.; Yang, Xiaoli; Goldner, Lori S.; Baskin, Tobias I.

    The polymer cellulose is one of the major components of the world's biomass with unique and fascinating characteristics such as its high tensile strength, renewability, biodegradability, and biocompatibility. Because of these distinctive aspects, cellulose has been the subject of enormous scientific and industrial interest, yet there are still fundamental open questions about cellulose biosynthesis. Cellulose is synthesized by a complex of transmembrane proteins called ``Cellulose Synthase A'' (CESA) in the plasma membrane. Studying the dynamics and kinematics of the CESA complex will help reveal the mechanism of cellulose synthesis and permit the development and validation of models of CESA motility. To understand what drives these complexes through the cell membrane, we used total internal reflection fluorescence microscopy (TIRFM) and variable angle epi-fluorescence microscopy to track individual, fluorescently-labeled CESA complexes as they move in the hypocotyl and root of living plants. A mean square displacement analysis will be applied to distinguish ballistic, diffusional, and other forms of motion. We report on the results of these tracking experiments. This work was funded by NSF/PHY-1205989.

  11. Microbial Cellulose Production from Bacteria Isolated from Rotten Fruit

    Directory of Open Access Journals (Sweden)

    B. E. Rangaswamy

    2015-01-01

    Full Text Available Microbial cellulose, an exopolysaccharide produced by bacteria, has unique structural and mechanical properties and is highly pure compared to plant cellulose. Present study represents isolation, identification, and screening of cellulose producing bacteria and further process optimization. Isolation of thirty cellulose producers was carried out from natural sources like rotten fruits and rotten vegetables. The bacterial isolates obtained from rotten pomegranate, rotten sweet potato, and rotten potato were identified as Gluconacetobacter sp. RV28, Enterobacter sp. RV11, and Pseudomonas sp. RV14 through morphological and biochemical analysis. Optimization studies were conducted for process parameters like inoculum density, temperature, pH, agitation, and carbon and nitrogen sources using Gluconacetobacter sp. RV28. The strain produced 4.7 g/L of cellulose at optimum growth conditions of temperature (30°C, pH (6.0, sucrose (2%, peptone (0.5%, and inoculum density (5%. Characterization of microbial cellulose was done by scanning electron microscopy (SEM.

  12. The Kinetics of Cellulose Grafting with Vinyl Acetate Monomer

    Directory of Open Access Journals (Sweden)

    Éva Borbély

    2005-11-01

    Full Text Available Cellulose is a natural raw material recurring in a great quantity. The demand touse it more and more widely is increasing. The production of cellulose derivates started asearly as the 19th century, however the modification of these materials meant the breakingup the fibrous structure, which made their use more difficult in paper industry. Themodified cellulose made by graft copolymerization, however, keeps its fibrous character,which provides a great advantage regarding its use. Grafting of industrial cellulose pulpwith vinyl-acetate allows for the production of grafted wood cellulose fibres that have athermoplastic layer on their surface. The binder fibre (fibrid produced in this way can beexcellently used for producing synthetic papers.In the first part of my experiments I dealt with choosing the parameters of graftcopolymerization which are best suited to various uses and after that I studied thedependence of graft reaction on the composition and properties of industrial celluloseapplied. The selection of the suitable reaction parameters was followed by the study ofreaction speed and activation energy. I have stated that the gross reaction of graftingindustrial cellulose with vinyl-acetate monomer is a second order reaction, which is provenby the fact that the invert of the momentary monomer concentration of the system plottedagainst time is a linear function. The rise of the curves, that is, the reaction speed increaseswhen the temperature in the range of 293–323 K is increasing, while the average activationenergy decreases.

  13. Cellulose fermentation by nitrogen-fixing anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Canale-Parola, E.

    1992-12-13

    In anaerobic natural environments cellulose is degraded to methane, carbon dioxide and other products by the combined activities of many diverse microorganisms. We are simulating processes occurring in natural environments by constructing biologically-defined, stable, heterogeneous bacterial communities (consortia) that we use as in vitro systems for quantitative studies of cellulose degradation under conditions of combined nitrogen deprivation. These studies include the investigation of (i) metabolic interactions among members of cellulose-degrading microbial populations, and (ii) processes that regulate the activity or biosynthesis of cellulolytic enzymes. In addition, we are studying the sensory mechanisms that, in natural environments, may enable motile cellulolytic bacteria to migrate toward cellulose. This part of our work includes biochemical characterization of the cellobiose chemoreceptor of cellulolytic bacteria. Finally, an important aspect of our research is the investigation of the mechanisms by which multienzyme complexes of anaerobic bacteria catalyze the depolymerization of crystalline cellulose and of other plant cell wall polysacchaddes. The research will provide fundamental information on the physiology and ecology of cellulose-fermenting, N{sub 2}-fixing bacteria, and on the intricate processes involved in C and N cycling in anaerobic environments. Furthermore, the information will be valuable for the development of practical applications, such as the conversion of plant biomass (e.g., agricultural, forestry and municipal wastes) to automotive fuels such as ethanol.

  14. Effect of cellulose whisker content on the properties of poly(ethylene-co-vinyl acetate)/cellulose composites.

    Science.gov (United States)

    Elanthikkal, Silviya; Gopalakrishnapanicker, Unnikrishnan; Varghese, Soney; Guthrie, James T; Francis, Tania

    2013-06-20

    The reinforcing effect of cellulose whiskers, produced from banana waste fibres, has been investigated using poly(ethylene-co-vinyl acetate) [EVA]/cellulose whisker composites. Cellulose whiskers, approximately 300 nm long and 30 nm wide, were obtained via a sulphuric acid hydrolysis method. The effects of the cellulose whisker loading on the thermal properties, mechanical properties and on the morphological features of the composites have been investigated. EVA copolymer with a vinyl acetate segment content of 40% has been used for composite fabrication. The developed composites showed superior thermal and mechanical properties relative to that of the EVA copolymer alone. Three theoretical models, namely the Halpin-Tsai model, the Kerner model and the Nicolais-Narkis model have been employed to provide a basis for the comparison of the results with the observations from the tensile investigations.

  15. Complete Genome Sequence of a Gluconacetobacter hansenii ATCC 23769 Isolate, AY201, Producer of Bacterial Cellulose and Important Model Organism for the Study of Cellulose Biosynthesis.

    Science.gov (United States)

    Pfeffer, Sarah; Mehta, Kalpa; Brown, R Malcolm

    2016-08-11

    The cellulose producer and model organism used for the study of cellulose biosynthesis, Gluconacetobacter hansenii AY201, is a variant of G. hansenii ATCC 23769. We report here the complete nucleotide sequence of G. hansenii AY201, information which may be utilized to further the research into understanding the genes necessary for cellulose biosynthesis.

  16. Exploring architecture of xyloglucan cellulose nanocrystal complexes through enzyme susceptibility at different adsorption regimes.

    Science.gov (United States)

    Dammak, Abir; Quémener, Bernard; Bonnin, Estelle; Alvarado, Camille; Bouchet, Brigitte; Villares, Ana; Moreau, Céline; Cathala, Bernard

    2015-02-09

    Xyloglucan (XG) is believed to act as a cementing material that contributes to the cross-linking and mechanical properties of the cellulose framework in plant cell walls. XG can adsorb to the cellulose nanocrystal (CNC) surface in vitro in order to simulate this in vivo relationship. The target of our work was to investigate the sorption behavior of tamarind seed XG on CNC extracted from cotton linters at different XG/CNC concentration ratios, that is, different adsorption regimes regarding the XG-CNC complex organization and the enzymatic susceptibility of XG. First, we determined the adsorption isotherm. Second, XG-CNC complexes were enzymatically hydrolyzed using a xyloglucan-specific endoglucanase in order to quantify the different XG fractions involved in binding to CNC and to determine adsorption regimes, that is, presence of loops, tails, and trains. Finally, the architecture of the XG-CNC complex was investigated by transmission electron microscopy imaging of negatively stained XG-CNC suspensions and XG immunolabeled suspensions at different XG/CNC concentration ratios, both before and after xyloglucanase hydrolysis process. This study revealed that an increasing XG/CNC concentration ratio led to a change in the XG binding organization to CNC. At low XG/CNC concentration ratios, almost all XG chains were bound as trains to the CNC surface. In contrast, at increasing XG/CNC concentration ratios, the proportion of loops and tails increases. The organization change induces CNC aggregation to form a cellulose/XG network at low XG/CNC regimes, whereas CNC remains in the form of individual particles at higher XG/CNC regimes. Results are discussed both regarding the biological role of XG in plant cell walls and in the perspective of designing new biobased materials.

  17. Fabrication and characterization of novel biomimetic PLLA/cellulose/hydroxyapatite nanocomposite for bone repair applications

    Energy Technology Data Exchange (ETDEWEB)

    Eftekhari, Samin [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); El Sawi, Ihab; Bagheri, Zahra Shaghayegh [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); Turcotte, Ginette [Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada); Bougherara, Habiba, E-mail: habiba.bougherara@ryerson.ca [Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3 (Canada)

    2014-06-01

    The purpose of this research is to develop and characterize a novel biomimetic nanocomposite that closely mimics the properties of real bone such as morphology, composition and mechanical characteristics. This novel porous nanocomposite is composed of cotton-sourced cellulose microcrystals, hydroxyapatite nanoparticles and poly L-lactide acid. A unique combination of commonly used fabrication procedures has been developed including pre-treatment of particles using a coupling agent. The effect of various weight ratios of the reinforcing agents was evaluated to assess their influence on the chemical, thermal, and mechanical properties of the nanocomposites. The prepared nanocomposites were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and compression testing. Our results indicated the presence of molecular interactions between all components leading to an increase of the crystallinity of the polymer from 50% to 80%. Compression test results revealed that increasing the weight ratio of microcrystalline cellulose/poly L-lactide acid and hydroxyapatite/poly L-lactide acid from 0.1 to 0.5 enhanced the compressive yield stress from 0.127 to 2.2 MPa and The Young's modulus from 6.6 to 38 MPa, respectively. It was found that the fabricated nanocomposites are comparable with the trabecular bone from compositional, structural, and mechanical point of view. - Highlights: • Fabrication of PLLA/HA/cellulose composites that mimic the spongeous bone • Homogenous dispersion of the reinforcing agents in the PLLA matrix was attained. • More efficient interface between the PLLA and the reinforcing agents was achieved. • Preliminary in vitro biocompatibility test showed the nontoxicity of the composite. • The crystallinity, the compressive strength and modulus were investigated.

  18. Rheological study of cellulose dissolved in aqueous ZnCl2 : Regenerated cellulosic fibres for textile applications

    OpenAIRE

    Ulfstad, Louise

    2013-01-01

    The most known regenerated cellulosic fiber is viscose, produced in a wet spinning process, but due to cost and environmental issues other processes have been developed. Lyocell fibers, produced in air-gap spinning, have superior dry and wet strenght and a lower environmental impact compared to viscose. Research in different cellulose solvent has increased significantly tha last decadess, due to an increased cotton price and a decreased paper production, providing more wood pulp to production...

  19. Use of Recombinant Cellulose-Binding Domains of Trichoderma reesei Cellulase as a Selective Immunocytochemical Marker for Cellulose in Protozoa

    OpenAIRE

    Linder, Markus; Winiecka-Krusnell, Jadwiga; Linder, Ewert

    2002-01-01

    Some unicellular organisms are able to encyst as a protective response to a harmful environment. The cyst wall usually contains chitin as its main structural constituent, but in some cases, as in Acanthamoeba, it consists of cellulose instead. Specific cytochemical differentiation between cellulose and chitin by microscopy has not been possible, due to the similarity of their constituent β-1,4-linked hexose backbones. Thus, various fluorescent brightening agents and lectins bind to both cellu...

  20. Screening of the effective cellulose-degradable strain and its application in the production of cellulose bioethanol

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Strains from the cellulose-containing environment were collected. Primary screening(by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection(by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains obtained were best suited for high performance cellulose degradation. Determination of sodium carboxymethylcellulose activity(CMCA) and filter paper activity(FPA) was accomplis...

  1. Particle size and packing characterization by diffuse light transmission

    Institute of Scientific and Technical Information of China (English)

    Henrik Ehlers; Jyrki Hein(a)m(a)ki; Jouko Yliruusi

    2012-01-01

    Particle size,packing density and blend composition of glass ballotini,microcrystalline cellulose pellets and theophylline granules were studied by diffuse light transmission.Diffuse visible light was directed to the sample and the intensity of the light transmitted to the opposite side of the sample was measured through a diffusing lens using a phototransistor.Light transmission was found to decrease with decreasing particle size and with increasing packing density.There was a correlation,though somewhat irregular,between light transmission and particle size for glass ballotini and microcrystalline cellulose pellets,and a strong near-linear correlation between light transmission and particle size for theophylline granules.The effect of packing density on light transmission was significant.Differentiating the composition of binary blends of microcrystalline cellulose pellets and glass ballotini and blends of theophylline granules was found possible on the basis of light transmission.The method proposed showed potential as a rapid,simple and inexpensive analytical tool for basic process diagnostics.

  2. Preparing cationic cotton linter cellulose with high substitution degree by ultrasonic treatment.

    Science.gov (United States)

    Zhang, Fulong; Pang, Zhiqiang; Dong, Cuihua; Liu, Zong

    2015-11-05

    As an important cellulose derivative, cationic cellulose has becoming an attractive material. However, it remains challenging to produce cationic cellulose with high substitute degree. In this paper, we successfully increased the substitute degree of cationic cellulose by introducing ultrasonic treatment, which efficiently breaks hydrogen bonds of the chemical structure of cationic cellulose. Properties of cationic cellulose were studied by scanning electron spectroscope (SEM), contact angle, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Experimental results show that the cationic cellulose has rougher surface and lower crystallinity degree as compared to the original sample. TGA analysis verifies that the thermostability of CLC decreases after the cationic modification. The residual of the cationic cellulose (25 wt%) after pyrolysis increases significantly as compared to that of the original cellulose (15 wt%).

  3. Grafted cellulose for PAHs removal present in industrial discharge waters

    Science.gov (United States)

    Euvrard, Elise; Druart, Coline; Poupeney, Amandine; Crini, Nadia; Vismara, Elena; Lanza, Tommaso; Torri, Giangiacomo; Gavoille, Sophie; Crini, Gregorio

    2014-05-01

    Keywords: cellulose; biosorbent; PAHs; polycontaminated wastewaters; trace levels. Polycyclic aromatic hydrocarbons (PAHs), chemicals essentially formed during incomplete combustion of organic materials from anthropogenic activities, were present in all compartments of the ecosystem, air, water and soil. Notably, a part of PAHs found in aquatic system was introduced through industrial discharge waters. Since the Water Framework Directive has classified certain PAHs as priority hazardous substances, industrials are called to take account this kind of organic pollutants in their global environmental concern. Conventional materials such as activated carbons definitively proved their worth as finishing treatment systems but remained costly. In this study, we proposed to use cellulose grafted with glycidyl methacrylate [1] for the removal of PAHs present in discharge waters of surface treatment industries. Firstly, to develop the device, we worked with synthetic solutions containing 16 PAHs at 500 ng/L. Two types of grafted cellulose were tested over a closed-loop column with a concentration of 4g cellulose/L: cellulose C2 with a hydroxide group and cellulose C4 with an amine group. No PAH was retained by the raw cellulose whereas abatement percentages of PAHs were similar between C2 and C4 (94% and 98%, respectively, for the sum of the 16 PAHs) with an experiment duration of 400 min (corresponding to about 20 cycles through grafted cellulose). Secondly, to determine the shorter time to abate the amount maximum of PAHs through the system, a kinetic was realized from 20 min (one cycle) to 400 min with C4. The steady state (corresponding to about 95% of abatement of the total PAHs) was reached at 160 min. Finally, the system was then tested with real industrial discharge waters containing both mineral and organic compounds. The results indicated that the abatement percentage of PAHs was similar between C2 and C4, corroborating the tests with synthetic solution. In return

  4. Antibacterial paperboard packaging using microfibrillated cellulose.

    Science.gov (United States)

    Lavoine, Nathalie; Desloges, Isabelle; Manship, Brigitte; Bras, Julien

    2015-09-01

    The industry and consumers are focusing more and more on the development of biodegradable and lightweight food-packaging materials, which could better preserve the quality of the food and improve its shelf-life. In an attempt to meet these requirements, this study presents a novel bio-substrate able to contain active bio-molecules for future food-packaging applications. Based on a paperboard substrate, the development of an antibacterial bio-packaging material is, therein, achieved using a chlorhexidine digluconate (CHX) solution as a model of an antibacterial molecule, mixed with microfibrillated cellulose (MFC) and used as coating onto paperboard samples. AFM and FE-SEM analyses were performed to underline the nanoporous MFC network able to trap and to progressively release the CHX molecules. The release study of CHX was conducted in an aqueous medium and showed a lower proportion (20 %) of CHX released when using MFC. This led to the constant release of low amounts of CHX over 40 h. Antibacterial tests were carried out to assess the preservation of the antibacterial activity of the samples after the release studies. Samples remained active against Bacillus subtilis, with better results being obtained when MFC was used. The preservation of the quality of a model food was finally evaluated paving the way for future promising applications in the food packaging industry.

  5. Rheology of nanocrystalline cellulose aqueous suspensions.

    Science.gov (United States)

    Shafiei-Sabet, Sadaf; Hamad, Wadood Y; Hatzikiriakos, Savvas G

    2012-12-11

    The rheological properties and microstructure of nanocrystalline cellulose (NCC) aqueous suspensions have been investigated at different concentrations. The suspension is isotropic up to 3 wt %, and phase separates to liquid crystalline and isotropic domains at higher concentrations where the samples exhibit a fingerprint texture and the viscosity profile shows a three-region behavior, typical of liquid crystals. The suspension behaves as a rheological gel at even higher concentrations where the viscosity profile shows a single shear thinning behavior over the whole range of shear rates investigated. The effects of ultrasound energy and temperature on the rheological properties and structure of these suspensions were studied using polarized optical microscopy and rheometry. Our results indicate that the amount of applied ultrasound energy affects the microstructure of the suspensions and the pitch of the chiral nematic domains. The viscosity profile is changed significantly at low shear rates, whereas the viscosity of biphasic suspensions at intermediate and high shear rates decreased with increasing temperature. This suggests that, between 30 and 40 °C, structural rearrangement takes place. At higher concentrations of about 10 wt %, the temperature has no significant effect on viscosity; however, a marked increase in viscosity has been observed at around 50 °C. Finally, the Cox-Merz rule was found to fail after a critical concentration, thereby implying significant structural formation. This critical concentration is much higher for sonicated compared to unsonicated suspensions.

  6. Catalytic hydrolysis of cellulose into furans

    Science.gov (United States)

    Shi, Chengmei; Tao, Furong; Cui, Yuezhi

    2016-12-01

    Chromium chloride in 4-(3-methylimidazolium-1-yl)butane-1-sulfonic acid hydrogen sulfate (IL-1) was found to effectively catalyze the hydrolysis of microcrystalline cellulose (MCC) at 150°C for 300 min to achieve 87.8% conversion to a slate of products. With a catalytic amount of CrCl3, the yields of 5-hydroxymethyl furfural (HMF) and furfural were up to 32.4 and 15.2%, respectively, small molecules levulinic acid (LA, 10.8%) and the total reducing sugars (TRS, 10.7%) were also generated. Through LC-MSD analysis and mass spectra, dimer of furan compounds as the main by-products were speculated, and the components of gas products were methane, ethane, CO, CO2, and H2. We suggested that IL-1 and CrCl3 exhibited a coordination interaction; the formation of the intermediate via the hydride shift played a key role in the formation of HMF. The catalyst was recycled and exhibited constant activity for five successive trials.

  7. Cellulose-Based Membranes for Solutes Fractionation

    Science.gov (United States)

    Anokhina, T. S.; Yushkin, A. A.; Volkov, V. V.; Antonov, S. V.; Volkov, A. V.

    This work was focused on investigation of industrial cellophane film as a membrane material for solvent nanofiltration. The effect of conditioning of cellophane membranes by stepwise changing of composition of ethanol-water binary mixtures (from ethanol to water and from water to ethanol) was studied. It was shown that such treatment leads to an increase of ethanol permeability more than two orders of magnitude over initial untreated film samples. Treated cellophane membranes possess the ethanol permeability coefficient comparable with the values for highly permeability glassy polymers. Investigation of cellophane swelling in water ethanol solutions allowed to conclude that during the treatment formation of porous in the film takes place due to increase of inter chain distances. Observed high ethanol permeability connected with the fact that formed porous structure remains after the replacement of water with ethanol. Also it was shown that rejection coefficients of a number of dyes (MW 350) were in good agreement with the degree of hydrophobicity/hydrophilicity and ability of the solvent to form hydrogen bonding with the solute molecules. It was demonstrated that cellulose-based membranes can be complimentary for other type of the membranes in fractionation of multi-components solutions.

  8. Conversion of cellulosic wastes to liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kuester, J.L.

    1980-09-01

    The current status and future plans for a project to convert waste cellulosic (biomass) materials to quality liquid hydrocarbon fuels is described. The basic approach is indirect liquefaction, i.e., thermal gasification followed by catalytic liquefaction. The indirect approach results in separation of the oxygen in the biomass feedstock, i.e., oxygenated compounds do not appear in the liquid hydrocarbon fuel product. The process is capable of accepting a wide variety of feedstocks. Potential products include medium quality gas, normal propanol, diesel fuel and/or high octane gasoline. A fluidized bed pyrolysis system is used for gasification. The pyrolyzer can be fluidized with recycle pyrolysis gas, steam or recycle liquefaction system off gas or some combination thereof. Tars are removed in a wet scrubber. Unseparated pyrolysis gases are utilized as feed to a modified Fischer-Tropsch reactor. The liquid condensate from the reactor consists of a normal propanol-water phase and a paraffinic hydrocarbon phase. The reactor can be operated to optimize for either product. The following tasks were specified in the statement of work for the contract period: (1) feedstock studies; (2) gasification system optimization; (3) waste stream characterization; and (4) liquid fuels synthesis. In addition, several equipment improvements were implemented.

  9. Conversion of bagasse cellulose into ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Cuzens, J.E.

    1997-11-19

    The study conducted by Arkenol was designed to test the conversion of feedstocks such as sugar cane bagasse, sorghum, napier grass and rice straw into fermentable sugars, and then ferment these sugars using natural yeasts and genetically engineered Zymomonis mobilis bacteria (ZM). The study did convert various cellulosic feedstocks into fermentable sugars utilizing the patented Arkenol Concentrated Acid Hydrolysis Process and equipment at the Arkenol Technology Center in Orange, California. The sugars produced using this process were in the concentration range of 12--15%, much higher than the sugar concentrations the genetically engineered ZM bacteria had been developed for. As a result, while the ZM bacteria fermented the produced sugars without initial inhibition, the completion of high sugar concentration fermentations was slower and at lower yield than predicted by the National Renewable Energy Laboratory (NREL). Natural yeasts performed as expected by Arkenol, similar to the results obtained over the last four years of testing. Overall, at sugar concentrations in the 10--13% range, yeast produced 850090% theoretical ethanol yields and ZM bacteria produced 82--87% theoretical yields in 96 hour fermentations. Additional commercialization work revealed the ability to centrifugally separate and recycle the ZM bacteria after fermentation, slight additional benefits from mixed culture ZM bacteria fermentations, and successful utilization of defined media for ZM bacteria fermentation nutrients in lieu of natural media.

  10. STUDY ADSORPTION DESORPTION OF MANGANESE(II USING IMPREGNATED CHITIN-CELLULOSE AS ADSORBENT

    Directory of Open Access Journals (Sweden)

    Aldes Lesbani

    2015-03-01

    Full Text Available Abstract- Study adsorption desorption of manganese(II using impregnated chitin-cellulose as adsorbent has been carried out. Chitin was extracted from snail shell and cellulose isolated from rice straw. Chitin and cellulose were impregnated using thiourea as impregnant agent. Characterization of chitin and cellulose was performed using FTIR spectroscopy, determination of water content, and ash content, while impregnated chitin-cellulose was characterized using FTIR spectrophotometer and X-Ray diffractometer. The adsorption of Mn(II on impregnated chitin-cellulose was studied through determination of adsorption time and the influence of Mn(II concentration, while desorption was carried out sequentially using various reagents. The results shown that chitin and cellulose from extraction processes are has similar FTIR spectrum compared to chitin and cellulose standard. The FTIR spectrum of impregnated chitin-cellulose shows both vibration of chitin and cellulose appeared and indicated successfully impregnate. These results were also equal to XRD pattern analysis. The water and ash contents of chitin are 0.038% and 0.043 while for cellulose are 0.184% and 0.165%, respectively. The adsorption of Mn(II on chitin and cellulose are quite similar kinetically, while adsorption of Mn(II on impregnated chitin-cellulose is higher at the same time with chitin and cellulose. In the low concentration of Mn(II, adsorption phenomena are similar on chitin, cellulose, and impregnated chitin-cellulose. Desorption process of Mn(II on the adsorbents shows sodium etilenediamine tetra acetate able to desorp Mn(II up to 68% higher than other reagents. Keywords: Manganese(II, Chitin, Cellulose, Impregnated Chitin-Cellulose

  11. Synthesis of Platinum Nanoparticles from K2PtCl4 Solution Using Bacterial Cellulose Matrix

    Directory of Open Access Journals (Sweden)

    H. F. Aritonang

    2014-01-01

    Full Text Available Platinum (Pt nanoparticles have been synthesized from a precursor solution of potassium tetrachloroplatinate (K2PtCl4 using a matrix of bacterial cellulose (BC. The formation of Pt nanoparticles occurs at the surface and the inside of the BC membrane by reducing the precursor solution with a hydrogen gas reductant. The Pt nanoparticles obtained from the variations of precursor concentration, between 3 mM and 30 mM, and the formation of Pt nanoparticles have been studied using X-ray diffraction (XRD, scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS, and thermogravimetry analysis (TGA. Based on X-ray diffraction patterns, Pt particles have sizes between 6.3 nm and 9.3 nm, and the Pt particle size increases with an increase in precursor concentration. The morphology of the Pt nanoparticles was observed by SEM-EDS and the content of Pt particles inside the membrane is higher than that on the surface of BC membranes. This analysis corresponds to the TGA analysis, but the TGA analysis is more representative in how it describes the content of Pt particles in the BC membrane.

  12. Studies on Bacteria?Like Particles Sampled from the Stratosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wainwright, M; Weber, P; Smith, J; Hutcheon, I; Klyce, B; Wickramasinghe, N; Narlikar, J; Rajaratnam, P

    2004-07-16

    Bacteria-like particles recovered from the stratosphere and deposited on cellulose acetate membranes have been analyzed to confirm their bacterial nature. One particle appeared to be attached to an inorganic particle apparently by mucoid material typically produced by bacteria. A filamentous structure, morphologically similar to a fungal hypha, was also observed. EDS analysis showed that the particles were all non-mineral and therefore could be biological in nature. However, the composition several clumps of nanobacteria-sized particles were found, by SIMS analysis, to be inconsistent with that of bacteria. The results show that it is dangerous to assume that bacteria-like particles seen under scanning electron microscopy are necessarily bacteria.

  13. Revealing strong nanocomposite hydrogels reinforced by cellulose nanocrystals: insight into morphologies and interactions.

    Science.gov (United States)

    Yang, Jun; Zhao, Jing-Jing; Xu, Feng; Sun, Run-Cang

    2013-12-26

    Understanding the reinforcement mechanism by dispersing nanoscale particles into a polymer matrix is a critical challenge toward refining control of the composite properties. In this paper, the morphologies and interactions of cellulose nanocrystal/poly(acrylic acid) (CNC/PAA) nanocomposite hydrogels are demystified based on a facile synthetic platform. Two sources of CNCs with different aspect ratios are applied to model the reinforcement process, and the uniaxial tensile measurements indicate that the CNC aspect ratio and the nanocomposite mechanical behaviors are coupled, where the values of aspect ratios and nonpermanent interactions between the fillers and matrix dominate the reinforcement. Dynamic mechanical analysis is performed to examine the nature of the constrained polymer as the semicrystalline fractions, and the results indicate that polymer chain mobility in the vicinity of CNC surfaces is significantly reduced, providing new insight into the origin of the reinforcement mechanism. Rheological analysis and transmission electron microscopy observations show that both stepwise dissociation and polymer chain rearrangements contribute to the viscoelastic behaviors of the nanocomposite hydrogels. The increased modulus of the hydrogels is correlated to the volume of the constrained polymer, where the CNCs impart significant enhancement to the entanglement network. This study of the structure-property relationship deepens the understanding of the filler reinforcement mechanism and provides valuable knowledge for designing high performance nanocomposite hydrogels from cellulose as a raw material.

  14. Interparticle interactions mediated superspin glass to superferromagnetic transition in Ni-bacterial cellulose aerogel nanocomposites

    Science.gov (United States)

    Thiruvengadam, V.; Vitta, Satish

    2016-06-01

    The interparticle interactions in the magnetic nanocomposites play a dominant role in controlling phase transitions: superparamagnetic to superspin glass and to superferromagnetic. These interactions can be tuned by controlling the size and number density of nanoparticles. The aerogel composites, 0.3Ni-BC and 0.7Ni-BC, consisting of Ni nanoparticles distributed in the bacterial cellulose have been used as a model system to study these interactions. Contrary to conventional approach, size of Ni-nanoparticles is not controlled and allowed to form naturally in bacterial cellulose template. The uncontrolled growth of Ni results in the formation of nanoparticles with 3 different size distributions - 100 nm particles in voids formed by reticulate structure. At room temperature, the composites exhibit a weakly ferromagnetic behaviour with a coercivity of 40 Oe, which increases to 160 Oe at 10 K. The transition from weakly ferromagnetic state to superferromagnetic state at low temperatures is mediated by the superspin glass state at intermediate temperatures via the interparticle interactions aided by nanoparticles present along the length of fibres. A temperature dependent microstructural model has been developed to understand the magnetic behaviour of nanocomposite aerogels.

  15. Cotton-based Cellulose Nanomaterials for Applications in Composites and Electronics

    Science.gov (United States)

    Farahbakhsh, Nasim

    A modern society demands development of highly valued and sustainable products via innovative process technologies and utilizing bio-based alternatives for petroleum based materials. Systematic comparative study of nanocellulose particles as a biodegradable and renewable reinforcing agent can help to develop criteria for selecting an appropriate candidate to be incorporated in polymer nanocomposites. Of particular interest has been nanocellulosic materials including cellulose nanocrystal (CNC) and micro/nanofibrilated cellulose (MFC/NFC) which possess a hierarchical structure that permits an ordered structure with unique properties that has served as building blocks for the design of green and novel materials composites for applications in flexible electronics, medicine and composites. Key differences exist in nanocellulosic materials as a result the process by which the material is produced. This research demonstrates the applicability for the use of recycled cotton as promising sustainable material to be utilized as a substrate for electronic application and a reinforcing agent choice that can be produced without any intensive purification process and be applied to synthetic-based polymer nanocomposites in melt-processing. (Abstract shortened by ProQuest.).

  16. Use of mineral pigments in fabrication of superhydrophobically engineered cellulosic paper

    Directory of Open Access Journals (Sweden)

    Jing Shen

    2012-11-01

    Full Text Available Superhydrophobic materials have a lot of interesting potential applications. The self-cleaning property is a unique feature. Rendering the water-loving cellulosic paper superhydrophobic can open the door for value-added applications. Superhydrophobic paper is a fairly new area, and only very limited scientific publications are available in the literature. Among these publications, the topics on the use of mineral pigments in fabrication of superhydrophobic structures account for a large proportion. During the fabrication process, mineral pigments, e.g., silica, precipitated calcium carbonate, and clay, generally need to be hydrophobized, either directly or indirectly. Mineral pigments can be applied to cellulosic paper by surface treatment or wet-end filling, and good dispersabilities of these pigments are always highly demanded. A key mechanistic point is that by tunable particle packing or fabrication, mineral pigments may exhibit surface-roughening effects, which are critical for superhydrophobicity development. The roughening of a hydrophobic surface helps to enhance hydrophobicity. Possible concepts such as nano-structuring or controllable surface patterning of mineral pigments may help to improve superhydrophobicity. Environmental friendliness will also guide the scientific/technical development in this area.

  17. Preparation and characterization of transparent PMMA-cellulose-based nanocomposites.

    Science.gov (United States)

    Kiziltas, Esra Erbas; Kiziltas, Alper; Bollin, Shannon C; Gardner, Douglas J

    2015-01-01

    Nanocomposites of polymethylmethacrylate (PMMA) and cellulose were made by a solution casting method using acetone as the solvent. The nanofiber networks were prepared using three different types of cellulose nanofibers: (i) nanofibrillated cellulose (NFC), (ii) cellulose nanocrystals (CNC) and (iii) bacterial cellulose from nata de coca (NDC). The loading of cellulose nanofibrils in the PMMA varied between 0.25 and 0.5 wt%. The mechanical properties of the composites were evaluated using a dynamic mechanical thermal analyzer (DMTA). The flexural modulus of the nanocomposites reinforced with NDC at the 0.5 wt% loading level increased 23% compared to that of pure PMMA. The NFC composite also exhibited a slightly increased flexural strength around 60 MPa while PMMA had a flexural strength of 57 MPa. The addition of NDC increased the storage modulus (11%) compared to neat PMMA at room temperature while the storage modulus of PPMA/CNC nanocomposite containing 0.25 and 0.5 wt% cellulose increased about 46% and 260% to that of the pure PMMA at the glass transition temperature, respectively. Thermogravimetric analysis (TGA) indicated that there was no significant change in thermal stability of the composites. The UV-vis transmittance of the CNF nanocomposites decreased by 9% and 27% with the addition of 0.25 wt% CNC and NDC, respectively. This work is intended to spur research and development activity for application of CNF reinforced PMMA nanocomposites in applications such as: packaging, flexible screens, optically transparent films and light-weight transparent materials for ballistic protection.

  18. Ultrafiltration and Nanofiltration Multilayer Membranes Based on Cellulose

    KAUST Repository

    Livazovic, Sara

    2016-06-09

    Membrane processes are considered energy-efficient for water desalination and treatment. However most membranes are based on polymers prepared from fossil petrochemical sources. The development of multilayer membranes for nanofiltration and ultrafiltration, with thin selective layers of naturally available cellulose, has been hampered by the availability of non-aggressive solvents. We propose the manufacture of cellulose membranes based on two approaches: (i) silylation, coating from solutions in tetrahydrofuran, followed by solvent evaporation and cellulose regeneration by acid treatment; (ii) casting from solution in 1-ethyl-3-methylimidazolum acetate ([C2mim]OAc), an ionic liquid, followed by phase inversion in water. In the search for less harsh, greener membrane manufacture, the combination of cellulose and ionic liquid is of high interest. Due to the abundance of OH groups and hydrophilicity, cellulose-based membranes have high permeability and low fouling tendency. Membrane fouling is one of the biggest challenges in membrane industry and technology. Accumulation and deposition of foulants onto the surface reduce membrane efficiency and requires harsh chemical cleaning, therefore increasing the cost of maintenance and replacement. In this work the resistance of cellulose 5 membranes towards model organic foulants such as Suwanee River Humic Acid (SRHA) and crude oil have been investigated. Cellulose membrane was tested in this work for oil-water (o/w) separation and exhibited practically 100 % oil rejection with good flux recovery ratio and membrane resistivity. The influence of anionic, cationic and ionic surfactant as well as pH and crude oil concentration on oil separation was investigated, giving a valuable insight in experimental and operational planning.

  19. Application of ethyl cellulose, microcrystalline cellulose and octadecanol for wax based floating solid dispersion pellets.

    Science.gov (United States)

    Yan, Hong-Xiang; Zhang, Shuang-Shuang; He, Jian-Hua; Liu, Jian-Ping

    2016-09-01

    The present study aimed to develop and optimize the wax based floating sustained-release dispersion pellets for a weakly acidic hydrophilic drug protocatechuic acid to achieve prolonged gastric residence time and improved bioavailability. This low-density drug delivery system consisted of octadecanol/microcrystalline cellulose mixture matrix pellet cores prepared by extrusion-spheronization technique, coated with drug/ethyl cellulose 100cp solid dispersion using single-step fluid-bed coating method. The formulation-optimized pellets could maintain excellent floating state without lag time and sustain the drug release efficiently for 12h based on non-Fickian transport mechanism. Observed by SEM, the optimized pellet was the dispersion-layered spherical structure containing a compact inner core. DSC, XRD and FTIR analysis revealed drug was uniformly dispersed in the amorphous molecule form and had no significant physicochemical interactions with the polymer dispersion carrier. The stability study of the resultant pellets further proved the rationality and integrity of the developed formulation.

  20. Microcrystalline cellulose-carboxymethyl cellulose sodium as an effective dispersant for drug nanocrystals: A case study.

    Science.gov (United States)

    Dan, JiXiu; Ma, YueQin; Yue, PengFei; Xie, YuanBiao; Zheng, Qin; Hu, PengYi; Zhu, WeiFeng; Yang, Ming

    2016-01-20

    This study is aimed at seeking an alternative dispersant for spray drying of drug nanosuspensions. The ideal dispersant is not only able to prevent the agglomeration of drug nanocrystals in the suspension state, but also it is able to preserve redispersibility of drug nanocrystals after drying. An active pharmaceutical ingredient (API) was used as a model drug. API nanosuspensions were prepared by homogenization and converted into nanocrystals powder (API-NP) with microcrystalline cellulose-carboxymethyl cellulose sodium (MCCS) via spray drying. It was found that MCCS was able to prevent the aggregation of API-NP in the suspension state and the agglomeration during spray-drying process, possibility due to its high Zeta potential and steric barrier from network structure, and reduction of API size at nanoscale and incorporation into MCCS network structure did not affect the solid state of API as evidenced by DSC and XRD analysis. The spray-dried API-NP/MCCS powders exhibited excellent sphere-shape performance, and could easily redispersed to API-NC suspensions state. Dissolution of the spray-dried API-NP was distinctly superior to those of the crude powder and physical mixture, respectively. Within 30 min, approximate 85.87% of API was dissolved from the API-NP/MCCS. MCCS was demonstrated to be an effective dispersant for spray-dried drug nanocrystals and preservation of the nanocrystals associated with excellent redispersibility.

  1. Dental glass ionomer cement reinforced by cellulose microfibers and cellulose nanocrystals.

    Science.gov (United States)

    Silva, Rafael M; Pereira, Fabiano V; Mota, Felipe A P; Watanabe, Evandro; Soares, Suelleng M C S; Santos, Maria Helena

    2016-01-01

    The aim of this work was to evaluate if the addition of cellulose microfibers (CmF) or cellulose nanocrystals (CNC) would improve the mechanical properties of a commercial dental glass ionomer cement (GIC). Different amounts of CmF and CNC were previously prepared and then added to reinforce the GIC matrix while it was being manipulated. Test specimens with various concentrations of CmF or CNC in their total masses were fabricated and submitted to mechanical tests (to evaluate their compressive and diametral tensile strength,modulus, surface microhardness and wear resistance) and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The incorporation of CmF in the GIC matrix did not greatly improve the mechanical properties of GIC. However, the addition of a small amount of CNC in the GIC led to significant improvements in all of the mechanical properties evaluated: compressive strength (increased up to 110% compared with the control group), elastic modulus increased by 161%, diametral tensile strength increased by 53%, and the mass loss decreased from 10.95 to 3.87%. Because the composites presented a considerable increase in mechanical properties, the modification of the conventional GIC with CNC can represent a new and promising dental restorative material.

  2. Bacterial cellulose and bacterial cellulose/polycaprolactone composite as tissue substitutes in rabbits' cornea

    Directory of Open Access Journals (Sweden)

    Rodrigo V. Sepúlveda

    Full Text Available ABSTRACT: In order to test the performance of bacterial cellulose/polycaprolactone composite (BC/PCL and pure bacterial cellulose (BC as tissue substitutes in rabbits' cornea, a superficial ulcer containing 5mm in diameter and 0.2mm deep was made in the right cornea of 36 rabbits, then a interlayer pocket was created from the basis of this ulcer. Twelve rabbits received BC/PCL membrane and 12 were treated with BC membranes, both membranes with 8mm in diameter. The remaining rabbits received no membrane constituting the control group. The animals were clinically followed up for 45 days. Three animals of each group were euthanized at three, seven, 21, and 45 days after implantation for histological examination of the cornea along with the implant. Clinical observation revealed signs of moderate inflammatory process, decreasing from day 20th in the implanted groups. Histology showed absence of epithelium on the membranes, fibroplasia close to the implants, lymph inflammatory infiltrate with giant cells, collagen disorganization, with a predominance of immature collagen fibers in both groups with implants. Although inflammatory response is acceptable, the membranes used does not satisfactorily played the role of tissue substitute for the cornea during the study period.

  3. Bacterial cellulose and bacterial cellulose-vaccarin membranes for wound healing.

    Science.gov (United States)

    Qiu, Yuyu; Qiu, Liying; Cui, Jing; Wei, Qufu

    2016-02-01

    Bacterial cellulose (BC) and bacterial cellulose-vaccarin (BC-Vac) membranes were successfully produced in large scale. BC was synthesized by Gluconacetobacter xylinum. BC-Vac membranes were prepared by immersing BC in vaccarin solution. The surface morphologies of BC and BC-Vac membranes were examined by a scanning electron microscope (SEM) and an atomic force microscopy (AFM). The images showed that BC-Vac exhibited the characteristic 3D nanofibrillar network of BC matrix but there was adhesion between fibers. The mechanical properties of BC and BC-Vac membranes were evaluated and the results indicated that the adding of drug vaccarin into the BC membranes increased the malleability indicated by the increment in elongation at break compared with BC. Fourier transform infrared spectroscopy (FTIR) analysis was conducted to confirm the incorporation of vaccarin in BC-Vac and investigate the hydroxyl interactions between BC and drug vaccarin. Cell viability and cell attachment studies demonstrated that BC and BC-Vac membranes had no cytotoxicity and could be a good carrier for cell growth. The wound healing performance was examined in vivo by rat skin models. Histological observations revealed that wounds treated with BC-Vac epithelialized and regenerated faster than treated with BC. Therefore, BC-Vac was considered as a potential candidate for wound dressing materials.

  4. Catalytic Fast Pyrolysis of Cellulose Using Nano Zeolite and Zeolite/Matrix Catalysts in a GC/Micro-Pyrolyzer.

    Science.gov (United States)

    Lee, Kyong-Hwan

    2016-05-01

    Cellulose, as a model compound of biomass, was catalyzed over zeolite (HY,.HZSM-5) and zeolite/matrix (HY/Clay, HM/Clay) in a GC/micro-pyrolyzer at 500 degrees C, to produce the valuable products. The catalysts used were pure zeolite and zeolite/matrix including 20 wt% matrix content, which were prepared into different particle sizes (average size; 0.1 mm, 1.6 mm) to study the effect of the particle size of the catalyst for the distribution of product yields. Catalytic pyrolysis had much more volatile products as light components and less content of sugars than pyrolysis only. This phenomenon was strongly influenced by the particle size of the catalyst in catalytic fast pyrolysis. Also, in zeolite and zeolite/matrix catalysts the zeolite type gave the dominant impact on the distribution of product yields.

  5. Evaluation of Wood and Cellulosic Materials as Fillers in Artificial Diets for Lyctus africanus Lesne (Coleoptera: Bostrichidae

    Directory of Open Access Journals (Sweden)

    Titik Kartika

    2015-07-01

    Full Text Available We studied the usefulness of wood- and cellulose-based diets for L. africanus Lesne. Three diets were prepared which differed on the base ingredients; wood particles (Diet 1, cellulose powder (Diet 2, and alpha-cellulose (Diet 3. The diets were provided to adult L. africanus and the number of larvae, as well as the number of adults that emerged sex ratio, and body weight of the progeny was determined. Findings indicated similar results for the number of larvae, sex ratio and body weight of the emerged L. africanus fed on each diet. However, the number of adult produced by L. africanus on Diet 3 was significantly lower. The results indicate that the amount of vital nutrients is not the only important factor in selecting a suitable diet for L. africanus because the filler used in artificial diets influences the beetles overall population growth. For the population upon which the diets were tested, Diet 1 and Diet 2 could be utilized to rear beetles in the laboratory.

  6. Cellulose Nanofibril Based-Aerogel Microreactors: A High Efficiency and Easy Recoverable W/O/W Membrane Separation System

    Science.gov (United States)

    Zhang, Fang; Ren, Hao; Dou, Jing; Tong, Guolin; Deng, Yulin

    2017-01-01

    Hereby we report a novel cellulose nanofirbril aerogel-based W/O/W microreactor system that can be used for fast and high efficient molecule or ions extraction and separation. The ultra-light cellulose nanofibril based aerogel microspheres with high porous structure and water storage capacity were prepared. The aerogel microspheres that were saturated with stripping solution were dispersed in an oil phase to form a stable water-in-oil (W/O) suspension. This suspension was then dispersed in large amount of external waste water to form W/O/W microreactor system. Similar to a conventional emulsion liquid membrane (ELM), the molecules or ions in external water can quickly transport to the internal water phase. However, the microreactor is also significantly different from traditional ELM: the water saturated nanocellulose cellulose aerogel microspheres can be easily removed by filtration or centrifugation after extraction reaction. The condensed materials in the filtrated aerogel particles can be squeezed and washed out and aerogel microspheres can be reused. This novel process overcomes the key barrier step of demulsification in traditional ELM process. Our experimental indicates the novel microreactor was able to extract 93% phenol and 82% Cu2+ from external water phase in a few minutes, suggesting its great potential for industrial applications.

  7. Addressing the Recalcitrance of Cellulose Degradation through Cellulase Discovery, Nano-scale Elucidation of Molecular Mechanisms, and Kinetic Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Larry P., Bergstrom, Gary; Corgie, Stephane; Craighead, Harold; Gibson, Donna; Wilson, David

    2011-06-13

    This research project was designed to play a vital role in the development of low cost sugars from cellulosic biomass and contributing to the national effort to displace fossil fuel usage in the USA transportation sector. The goal was to expand the portfolio of cell wall degrading enzymes through innovative research at the nano-scale level, prospecting for novel cellulases and building a kinetic framework for the development of more effective enzymatic conversion processes. More precisely, the goal was to elucidate the molecular mechanisms for some cellulases that are very familiar to members of our research team and to investigate what we hope are novel cellulases or new enzyme combinations from the world of plant pathogenic fungi and bacteria. Hydrolytic activities of various cellulases and cellulase cocktails were monitored at the nanoscale of cellulose fibrils and the microscale of pretreated cellulose particles, and we integrated this insight into a heterogeneous reaction framework. The over-riding approach for this research program was the application of innovative and cutting edge optical and high-throughput screening and analysis techniques for observing how cellulases hydrolyze real substrates.

  8. Ammonia fiber expansion (AFEX) pretreatment, enzymatic hydrolysis, and fermentation on empty palm fruit bunch fiber (EPFBF) for cellulosic ethanol production.

    Science.gov (United States)

    Lau, Ming J; Lau, Ming W; Gunawan, Christa; Dale, Bruce E

    2010-11-01

    Empty palm fruit bunch fiber (EPFBF), a readily available cellulosic biomass from palm processing facilities, is investigated as a potential carbohydrate source for cellulosic ethanol production. This feedstock was pretreated using ammonia fiber expansion (AFEX) and enzymatically hydrolyzed. The best tested AFEX conditions were at 135 °C, 45 min retention time, water to dry biomass loading of 1:1 (weight ratio), and ammonia to dry biomass loading of 1:1 (weight ratio). The particle size of the pretreated biomass was reduced post-AFEX. The optimized enzyme formulation consists of Accellerase (84 μL/g biomass), Multifect Xylanase (31 μL/g biomass), and Multifect Pectinase (24 μL/g biomass). This mixture achieved close to 90% of the total maximum yield within 72 h of enzymatic hydrolysis. Fermentation on the water extract of this biomass affirms that nutrients solely from the pretreated EPFBF can support yeast growth for complete glucose fermentation. These results suggest that AFEX-treated EPFBF can be used for cellulosic biofuels production because biomass recalcitrance has been overcome without reducing the fermentability of the pretreated materials.

  9. The effect of low frequency ultrasound on the production and properties of nanocrystalline cellulose suspensions and films.

    Science.gov (United States)

    Csiszar, Emilia; Kalic, Petra; Kobol, Akos; Ferreira, Eduardo de Paulo

    2016-07-01

    Suspension of nanocrystalline cellulose (NCC) produced from bleached cotton by controlled sulphuric acid hydrolysis was treated with low frequency ultrasound at 20 kHz and 60% amplitude for 0, 1, 2, 5 and 10 min and the effects of sonication on the properties of both the cellulose nanocrystals and their aqueous suspensions were investigated. Furthermore, a series of nanocellulose films were manufactured from the suspensions that were sonicated for different periods of time and tested. Laser diffraction analysis and transmission electron microscopy proved that sonication not only disintegrated the large NCC aggregates (Dv50 14.7 μm) to individual nanowhiskers with an average length and width of 171 ± 57 and 17 ± 4 nm, respectively, but also degraded the nanocrystals and yielded shorter and thinner particles (118 ± 45 and 13 ± 3 nm, respectively) at 10-min sonication. The ultrasound-assisted disintegration to nano-sized cellulose whiskers decreased the optical haze of suspensions from 98.4% to 52.8% with increasing time from 0 to 10 min, respectively. Sonication of the suspensions significantly contributed to the preparation of films with low haze (high transparency) and excellent tensile properties. With the increasing duration of sonication, the haze decreased and the tensile strength rose gradually. Irrespectively of sonication, however, all films had an outstanding oxygen transmission rate in a range of 5.5-6.9 cm(3)/m(2)day, and a poor thermal stability.

  10. APPLICATION OF FILLERS IN CELLULOSIC PAPER BY SURFACE FILLING: AN INTERESTING ALTERNATIVE OR SUPPLEMENT TO WET-END ADDITION

    Directory of Open Access Journals (Sweden)

    Jing Shen,

    2012-01-01

    Full Text Available The application of fillers at the surface of cellulosic paper is an interesting and industrially-commercialized but not very well-known concept, in which the filler particles are essentially added to the voids of the fibrous matrixes. This so-called “surface filling” can be achieved by the use of fillers together with a polymer solution via film press or size press, an approach that is distinct from both wet-end filling and conventional coating of paper. As an easily practicable process, surface filling has some advantages over direct wet-end addition of fillers, such as minimizing the adverse effects of filler addition on paper strength. Efficient surface filling is somewhat dependent on the specific characteristics of both fillers and fibrous matrixes. Surface filling may provide interesting possibilities for the papermaking discipline; for example, it would open the door to maximizing the cost-effectiveness of paper mills, and efficiently adding new functionalities to cellulosic paper. From both practical and fundamental points of view, systematic exploration and understanding of surface filling of cellulosic paper would be of great significance to the papermaking industry.

  11. MICROBIAL FERMENTATION OF ABUNDANT BIOPOLYMERS: CELLULOSE AND CHITIN

    Energy Technology Data Exchange (ETDEWEB)

    Leschine, Susan

    2009-10-31

    Our research has dealt with seven major areas of investigation: i) characterization of cellulolytic members of microbial consortia, with special attention recently given to Clostridium phytofermentans, a bacterium that decomposes cellulose and produces uncommonly large amounts of ethanol, ii) investigations of the chitinase system of Cellulomonas uda; including the purification and characterization of ChiA, the major component of this enzyme system, iii) molecular cloning, sequence and structural analysis of the gene that encodes ChiA in C. uda, iv) biofilm formation by C. uda on nutritive surfaces, v) investigations of the effects of humic substances on cellulose degradation by anaerobic cellulolytic microbes, vi) studies of nitrogen metabolism in cellulolytic anaerobes, and vii) understanding the molecular architecture of the multicomplex cellulase-xylanase system of Clostridium papyrosolvens. Also, progress toward completing the research of more recent projects is briefly summarized. Major accomplishments include: 1. Characterization of Clostridium phytofermentans, a cellulose-fermenting, ethanol-producing bacterium from forest soil. The characterization of a new cellulolytic species isolated from a cellulose-decomposing microbial consortium from forest soil was completed. This bacterium is remarkable for the high concentrations of ethanol produced during cellulose fermentation, typically more than twice the concentration produced by other species of cellulolytic clostridia. 2. Examination of the use of chitin as a source of carbon and nitrogen by cellulolytic microbes. We discovered that many cellulolytic anaerobes and facultative aerobes are able to use chitin as a source of both carbon and nitrogen. This major discovery expands our understanding of the biology of cellulose-fermenting bacteria and may lead to new applications for these microbes. 3. Comparative studies of the cellulase and chitinase systems of Cellulomonas uda. Results of these studies indicate

  12. Cellulosic fibers and nonwovens from solutions: Processing and properties

    Science.gov (United States)

    Dahiya, Atul

    Cellulose is a renewable and bio-based material source extracted from wood that has the potential to generate value added products such as composites, fibers, and nonwoven textiles. This research was focused on the potential of cellulose as the raw material for fiber spinning and melt blowing of nonwovens. The cellulose was dissolved in two different benign solvents: the amine oxide 4-N-methyl morpholine oxide monohydrate (NMMO•H2O) (lyocell process); and the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([C 4MIM]Cl). The solvents have essentially no vapor pressure and are biologically degradable, making them environmentally advantageous for manufacturing processes. The objectives of this research were to: (1) characterize solutions of NMMO and [C4MIM]Cl; (2) develop processing techniques to melt blow nonwoven webs from cellulose using NMMO as a solvent; (3) electrospin cellulosic fibers from the [C4MIM]Cl solvent; (4) spin cellulosic single fibers from the [C4MIM]Cl solvent. Different concentration solutions of cellulose in NMMO and [C4MIM]Cl were initially characterized rheologically and thermally to understand their behavior under different conditions of stress, strain, and temperature. Results were used to determine processing conditions and concentrations for the melt blowing, fiber spinning, and electrospinning experiments. The cellulosic nonwoven webs and fibers were characterized for their physical and optical properties such as tensile strength, water absorbency, fiber diameter, and fiber surface. Thermal properties were also measured by thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. Lyocell webs were successfully melt blown from the 14% cellulose solution. Basis weights of the webs were 27, 79, and 141 g/m2 and thicknesses ranged from 0.3-0.9 mm, depending on die temperatures and die to collector distance. The average fiber diameter achieved was 2.3 microns. The 6% lyocell solutions exhibited

  13. Production of fuels by cellulose liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Datta, B.K.; McAuliffe, C.A. [Univ. of Manchester Institute of Science and Technology (United Kingdom)

    1993-12-31

    The effect of temperature on the liquefaction of cellulose was investigated in a range 200{degrees} to 350{degrees}C in aqueous medium with 5% pt/Al{sub 2}O{sub 3} catalyst, at 35 bars of hydrogen as reducing gas and a reaction time of 2 hours. Experiments were conducted in a 1 liter batch rocker autoclave reactor. The conversion increased from 46.5% at 200{degrees}C to 92.46% at 350{degrees}C, the oil yield increased from 18% at 200{degrees} to 33% at 350{degrees}C. At the high temperature, 350{degrees}C, the water soluble fraction and char formation decreased due to the conversion of the above to various gases. Moreover, ether solubles in water soluble fractions also decreased while the production of water increased from 8% at 200{degrees}C to 29% at 350{degrees}C. It suggests the possibility of removal of oxidants from the feedstocks as water. Initial dehydration reactions were obviously responsible for the high yield of water. Water yield increased gradually with the increase in temperature which was probably due to the dehydration of the intermediary products and the concurrent removal of oxygen atom as water instead of as CO or CO{sub 2}. At high temperatures, more CO{sub 2} gas was formed due to the water gas shift reaction. The formation of CO{sub 2} is favored over the formation of CO. At high temperatures more hydrocarbon gases were formed. Solvent extraction of the oils showed that the maximum percentage of carboxylic acids and phenolic compounds formed in comparison with carbonyl and neutral compounds when temperature increased.

  14. Surfactant-enhanced cellulose nanocrystal Pickering emulsions.

    Science.gov (United States)

    Hu, Zhen; Ballinger, Sarah; Pelton, Robert; Cranston, Emily D

    2015-02-01

    The effect of surfactants on the properties of Pickering emulsions stabilized by cellulose nanocrystals (CNCs) was investigated. Electrophoretic mobility, interfacial tension, confocal microscopy and three-phase contact angle measurements were used to elucidate the interactions between anionic CNCs and cationic alkyl ammonium surfactants didecyldimethylammonium bromide (DMAB) and cetyltrimethylammonium bromide (CTAB). Both surfactants were found to adsorb onto CNCs with concentration-dependent morphology. At low concentrations, individual surfactant molecules adsorbed with alkyl tails pointing outward leading to hydrophobic CNCs. At higher concentrations, above the surfactant's apparent critical micelle concentration, surfactant aggregate morphologies on CNCs were inferred and the hydrophobicity of CNCs decreased. DMAB, which has two alkyl tails, rendered the CNCs more hydrophobic than CTAB which has only a single alkyl tail, at all surfactant concentrations. The change in CNC wettability from surfactant adsorption was directly linked to emulsion properties; adding surfactant increased the emulsion stability, decreased the droplet size, and controlled the internal phase of CNC Pickering emulsions. More specifically, a double transitional phase inversion, from oil-in-water to water-in-oil and back to oil-in-water, was observed for emulsions with CNCs and increasing amounts of DMAB (the more hydrophobic surfactant). With CNCs and CTAB, no phase inversion was induced. This work represents the first report of CNC Pickering emulsions with surfactants as well as the first CNC Pickering emulsions that can be phase inverted. The ability to surface modify CNCs in situ and tailor emulsions by adding surfactants may extend the potential of CNCs to new liquid formulations and extruded/spray-dried materials.

  15. Understanding the Role of Physical Properties of Cellulose on Its Hydrolyzability by Cellulases

    Science.gov (United States)

    O'Dell, Patrick Jonathan

    Cellulose has long been explored as a potential feedstock for biofuel, however the recalcitrance of cellulose makes its conversion into biofuel much more challenging and economically unfavorable compared to well-established processes for converting starch or sugar feedstocks into biofuel. Enzymes capable of hydrolyzing cellulose into soluble sugars, glucose and cellobiose, have been found to work processively along cellulose microfibrils starting from reducing end groups. For this study, cellulose was produced and purified in-house from Gluconacetobacter xylinum cultures, and characterized by quantifying functional groups (aldehyde, ketone, and carboxyl groups) to determine the extent of oxidation of cellulose due to the processing steps. The main goal of this study was to look at the impacts of ultrasonication on cellulose's structure and the enzymatic hydrolyzability of cellulose. A completely randomized experimental design was used to test the effect of ultrasonication time and amplitude (intensity) on changes in cellulose fibril length, degree of polymerization, and rates and extents of hydrolysis. Results indicated that sonication time does significantly impact both the fibril length and average degree of polymerization of cellulose. The impact of ultrasonication on the hydrolyzability of cellulose by commercial cellulase and beta-glucosidase preparations could not be effectively resolved due to high variability in the experimental results. These studies serve as a basis for future studies understanding the role of cellulose microstructure in the mechanism of cellulase hydrolysis of cellulose.

  16. Impact of hemicelluloses and pectin on sphere-like bacterial cellulose assembly

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Jin; Catchmark, Jeffrey M

    It has been shown previously that certain strains of the bacterium Gluconacetobacter xylinus produce a spherical form of cellulose where the cellulose was formed in a layered fashion. The spherical cellulose was used as a model system to study cellulose–hemicellulose and cellulose–pectin composite formation. Cultures were produced in the presence of 0.5% (w/v) xyloglucan, xylan, arabinogalactan and pectin under agitating conditions. Cellulose samples with xyloglucan and pectin had different macro structures compared to other culture conditions. The micro structures showed that these two samples formed dense cellulose layers and had fewer cellulose fiber connections between layers. Cellulose samples with xylan and xyloglucan were found to contain more Iβ cellulose as found in higher plants, and exhibited decreases in crystallinity and crystalline sizes according to X-ray diffraction patterns. IR spectroscopy confirmed the changes in crystal allomorph. Cellulose was also grown in cultures containing different blends of both xyloglucan and pectin. Results show that xyloglucan had the dominant impact on the assembly of cellulose, suggesting that xyloglucan and pectin may interact with cellulose at different points in the assembly process, or in different regions. Bacterial cellulose and biomass yields indicated that xyloglucan and pectin could also stimulate the growth of cellulose.

  17. Site-directed mutagenesis of bacterial cellulose synthase highlights sulfur–arene interaction as key to catalysis

    OpenAIRE

    Sun, Shi-jing; Horikawa, Yoshiki; Wada, Masahisa; SUGIYAMA, Junji; Imai, Tomoya

    2016-01-01

    Cellulose is one of the most abundant biological polymers on Earth, and is synthesized by the cellulose synthase complex in cell membranes. Although many cellulose synthase genes have been identified over the past 25 years, functional studies of cellulose synthase using recombinant proteins have rarely been conducted. In this study, we conducted a functional analysis of cellulose synthase with site-directed mutagenesis, by using recombinant cellulose synthase reconstituted in living Escherich...

  18. Catalytic pyrolysis of cellulose in ionic liquid [bmim]OTf.

    Science.gov (United States)

    Qu, Guangfei; He, Weiwei; Cai, Yingying; Huang, Xi; Ning, Ping

    2016-09-05

    This study discussed the catalytic cracking process of cellulose in ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim]OTF) under 180°C, 240°C and 340°C, found that [bmim]OTF is an effective catalyst which can effectively reduce the pyrolysis temperature(nearly 200°C) of the cellulose. FRIR, XRD and SEM were used to analyze the structure characterization of fiber before and after the cracking; GC-MS was used for liquid phase products analysis; GC was used to analyze gas phase products. The results showed that the cellulose pyrolysis in [bmim]OTf mainly generated CO2, CO and H2, also generated 2-furfuryl alcohol, 2,5-dimethyl-1,5-diallyl-3-alcohol, 1,4-butyrolactone, 5-methyl furfural, 4-hydroxy butyric acid, vinyl propionate, 1-acetoxyl group-2-butanone, furan formate tetrahydrofuran methyl ester liquid product, and thus simulated the evolution mechanism of cellulose pyrolysis products based on the basic model of cellulose monomer.

  19. Genomics of aerobic cellulose utilization systems in actinobacteria.

    Directory of Open Access Journals (Sweden)

    Iain Anderson

    Full Text Available Cellulose degrading enzymes have important functions in the biotechnology industry, including the production of biofuels from lignocellulosic biomass. Anaerobes including Clostridium species organize cellulases and other glycosyl hydrolases into large complexes known as cellulosomes. In contrast, aerobic actinobacteria utilize systems comprised of independently acting enzymes, often with carbohydrate binding domains. Numerous actinobacterial genomes have become available through the Genomic Encyclopedia of Bacteria and Archaea (GEBA project. We identified putative cellulose-degrading enzymes belonging to families GH5, GH6, GH8, GH9, GH12, GH48, and GH51 in the genomes of eleven members of the actinobacteria. The eleven organisms were tested in several assays for cellulose degradation, and eight of the organisms showed evidence of cellulase activity. The three with the highest cellulase activity were Actinosynnema mirum, Cellulomonas flavigena, and Xylanimonas cellulosilytica. Cellobiose is known to induce cellulolytic enzymes in the model organism Thermobifida fusca, but only Nocardiopsis dassonvillei showed higher cellulolytic activity in the presence of cellobiose. In T. fusca, cellulases and a putative cellobiose ABC transporter are regulated by the transcriptional regulator CelR. Nine organisms appear to use the CelR site or a closely related binding site to regulate an ABC transporter. In some, CelR also regulates cellulases, while cellulases are controlled by different regulatory sites in three organisms. Mining of genome data for cellulose degradative enzymes followed by experimental verification successfully identified several actinobacteria species which were not previously known to degrade cellulose as cellulolytic organisms.

  20. Polyethylenimine surface layer for enhanced virus immobilization on cellulose

    Science.gov (United States)

    Tiliket, Ghania; Ladam, Guy; Nguyen, Quang Trong; Lebrun, Laurent

    2016-05-01

    Thin regenerated cellulose films are prepared by hydrolysis of cellulose acetate (CA). A polycation, namely polyethylenimine (PEI), is then adsorbed onto the films. From QCM-D analysis, PEI readily adsorbs from a 0.1% w/v solution in NaCl 0.2 M (ca. 100 ng cm-2). Further PEI adsorption steps at higher PEI concentrations induce a linear growth of the PEI films, suggesting that free adsorption sites still exist after the initial adsorption. The adsorbed PEI chains are resistant to variations of the ionic strength up to NaCl 1 M. Promisingly, the adsorption of T4D bacteriophages are 15-fold more efficient onto the PEI-treated, compared to the native regenerated cellulose films, as measured by QCM-D. This confirms the strong affinity between the negatively charged viruses and PEI, even at low PEI concentration, probably governed by strong electrostatic attractive interactions. This result explains the remarkable improvement of the affinity of medical masks for virus droplets when one of their cellulose layers was changed by two-PEI-functionalized cellulose-based filters.

  1. Structure and superparamagnetic behaviour of magnetite nanoparticles in cellulose beads

    Energy Technology Data Exchange (ETDEWEB)

    Correa, Jose R., E-mail: correa@fq.uh.cu [Department of General Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400 (Cuba); Bordallo, Eduardo [Sugar Cane-Cellulose Research Center, Cuba-9, Quivican (Cuba); Canetti, Dora [Department of Inorganic Chemistry, Faculty of Chemistry, University of Havana, Zapata and G, Havana City 10400 (Cuba); Leon, Vivian [Sugar Cane-Cellulose Research Center, Cuba-9, Quivican (Cuba); Otero-Diaz, Luis C. [Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040 (Spain); Electron Microscopy Center, Complutense University of Madrid, Madrid 28040 (Spain); Negro, Carlos [Chemical Engineering Department, Complutense University of Madrid, Madrid 28040 (Spain); Gomez, Adrian [Electron Microscopy Center, Complutense University of Madrid, Madrid 28040 (Spain); Saez-Puche, Regino [Department of Inorganic Chemistry-1, Complutense University of Madrid, Madrid 28040 (Spain)

    2010-08-15

    Superparamagnetic magnetite nanoparticles were obtained starting from a mixture of iron(II) and iron(III) solutions in a preset total iron concentration from 0.04 to 0.8 mol l{sup -1} with ammonia at 25 and 70 {sup o}C. The regeneration of cellulose from viscose produces micrometrical spherical cellulose beads in which synthetic magnetite were embedded. The characterization of cellulose-magnetite beads by X-ray diffraction, Scanning and Transmission Electron Microscopy and magnetic measurement is reported. X-ray diffraction patterns indicate that the higher is the total iron concentration and temperature the higher is the crystal size of the magnetite obtained. Transmission Electron Microscopy studies of cellulose-magnetite beads revealed the distribution of magnetite nanoparticles inside pores of hundred nanometers. Magnetite as well as the cellulose-magnetite composites exhibit superparamagnetic characteristics. Field cooling and zero field cooling magnetic susceptibility measurements confirm the superparamagnetic behaviour and the blocking temperature for the magnetite with a mean size of 12.5 nm, which is 200 K.

  2. Fibril orientation redistribution induced by stretching of cellulose nanofibril hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Josefsson, Gabriella; Gamstedt, E. Kristofer [The Ångström Laboratory, Department of Engineering Sciences, Division of Applied Mechanics, Uppsala University, Box 534, SE-751 21 Uppsala (Sweden); Ahvenainen, Patrik [Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 University of Helsinki (Finland); Mushi, Ngesa Ezekiel [Department of Fiber and Polymer Technology, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden)

    2015-06-07

    The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in a reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils.

  3. Taxonomic characterization of the cellulose-degrading bacterium NCIB 10462

    Energy Technology Data Exchange (ETDEWEB)

    Dees, C.; Ringleberg, D.; Scott, T.C. [Oak Ridge National Lab., TN (United States); Phelps, T. [Univ. of Tennessee, Knoxville, TN (United States)

    1994-06-01

    The gram negative cellulase-producing bacterium NCIB 10462 has been previously named Pseudomonas fluorescens subsp. or var. cellulosa. Since there is renewed interest in cellulose-degrading bacteria for use in bioconversion of cellulose to chemical feed stocks and fuels, we re-examined the characteristics of this microorganism to determine its proper taxonomic characterization and to further define it`s true metabolic potential. Metabolic and physical characterization of NCIB 10462 revealed that this was an alkalophilic, non-fermentative, gram negative, oxidase positive, motile, cellulose-degrading bacterium. The aerobic substrate utilization profile of this bacterium was found to have few characteristics consistent with a classification of P. fluorescens with a very low probability match with the genus Sphingomonas. Total lipid analysis did not reveal that any sphingolipid bases are produced by this bacterium. NCIB 10462 was found to grow best aerobically but also grows well in complex media under reducing conditions. NCIB 10462 grew slowly under full anaerobic conditions on complex media but growth on cellulosic media was found only under aerobic conditions. Total fatty acid analysis (MIDI) of NCIB 10462 failed to group this bacterium with a known pseudomonas species. However, fatty acid analysis of the bacteria when grown at temperatures below 37{degrees}C suggest that the organism is a pseudomonad. Since a predominant characteristic of this bacterium is it`s ability to degrade cellulose, we suggest it be called Pseudomonas cellulosa.

  4. Approaches to new derivatives of cellulose as designed pharmaceutical excipients

    Directory of Open Access Journals (Sweden)

    Schwarz Brigitte

    2003-01-01

    Full Text Available Recently, our group initiated a synthetic program directed at new derivatives of cellulose intended as novel pharmaceutical excipients. With several notable exceptions, the attempted regioselective introduction of chemical functionality into natural cellulose by direct chemical modification will result in heterogeneous products that are difficult to characterize and the preparation of which is insufficiently reproduceable. Approaches to the chemical polymerization of appropriate glucose monomers are available, leading to a degree of polymerization in the order of 100. However, the nature of these processes does not readily lend itself to the preparation of products comprising regularly arranged protecting groups in defined positions. We have chosen a mixed organic chemical-enzyme catalyzed approach based on a procedure of Kobayashi, Shoda, Donnelly and Church. Fluoride derivatives of cellobiose may be polymerized, under catalysis by cellobiose hydrolase, to form cellulose oligosaccharides of different chain lengths. We describe the chemical syntheses of cellobiose fluoride derivatives comprising protecting groups in defined positions of the reducing or nonreducing glucose moieties of cellobiose. Such derivatives may be polymerized to afford cellulose derivatives with protecting groups on alternate glucose units. The processing of these protected cellulose derivatives to afford novel biomimetic polymers will be described.

  5. Modified cellulosic dialyzer membranes: an investigative tool in thrombogenicity studies.

    Science.gov (United States)

    Mahiout, A; Meinhold, H; Kessel, M; Vienken, J; Baurmeister, U

    1988-01-01

    We have previously demonstrated that chemical modification of cellulosic membranes with dimethyl-amino-ethyl (DEAE) groups significantly improves membrane properties in terms of biocompatibility. Here, we show that DEAE substitution also alters the membrane's thrombogenic properties, and cellulosic membranes with various amounts of DEAE substitution were produced. Clinical dialyzers were constructed using two experimental membrane materials: modified cellulose-low (MC-low) and MC-high; standard unsubstituted cellulose was used as a control. Six patients were treated for a period of 3 weeks with each type of dialyzer and a heparin dose of less than 6000 IU/treatment. MC-low exhibited less extracorporeal beta-thromboglobulin and thromboxane B2 release than MC-high or Cuprophan. In addition, residual blood volume after clinical use was lower in the MC-low type. MC-low and MC-high induced less complement activation than Cuprophan, as characterized by extracorporeal C5a and C3a plasma concentrations (75% less C5a generation and 50 to 70% less C3a generation than unsubstituted cellulose).

  6. Zinc impregnated cellulose nanocomposites: Synthesis, characterization and applications

    Science.gov (United States)

    Ali, Attarad; Ambreen, Sidra; Maqbool, Qaisar; Naz, Sania; Shams, Muhammad Fahad; Ahmad, Madiha; Phull, Abdul Rehman; Zia, Muhammad

    2016-11-01

    Nanocomposite materials have broad applicability due to synergistic effect of combined components. In present investigation, cellulose isolated from citrus peel waste is used as a supporting material; impregnation of zinc oxide nanoparticles via co-precipitation method. The characterization of nano composite is carried out through Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and Thermo-gravimetric analysis (TGA) resulting less than 10 μm cellulose fiber and approx. 50 nm ZnO NPs. Zinc oxide impregnated cellulose (ZnO-Cel) exhibited significant bacterial devastation property when compared to ZnO NPs or Cellulose via disc diffusion and colony forming unit methods. In addition, the ZnO-Cel exhibited significant total antioxidant, and minor DPPH free radical scavenging and total reducing power activities. The nano composite also showed time dependent increase in photocatalytic by effectively degrading methylene blue dye up to 69.5% under sunlight irradiation within 90 min. The results suggest effective utilization of cellulose obtained from citrus waste and synthesis of pharmacologically important nano-composites that can be exploited in wound dressing; defence against microbial attack and healing due to antioxidative property, furthermore can also be used for waste water treatment.

  7. 基于溶胶-凝胶技术制备纳米纤维素的表征%Characterization of Nano-cellulose with Sol-gel Method

    Institute of Scientific and Technical Information of China (English)

    谢成; 刘志明; 王海英; 孟围

    2012-01-01

    通过傅里叶变换红外光谱、X射线衍射、热重、透射电子显微镜分析及激光粒度分析对基于溶胶-凝胶技术制备的纳米纤维素进行表征,结果表明原料微晶纤维素超分子结构为纤维素Ⅰ型,制备的纳米纤维素为纤维素Ⅱ型;微晶纤维素的结晶度为87.54%,纳米纤维素的结晶度为73.49%,纳米纤维素结晶度较微晶纤维素有所下降;制备的纳米纤维素热稳定性低于微晶纤维素;纳米纤维素平均粒度425 nm,粒度分布呈现正态分布;纳米纤维素长径比为5∶1~40∶1。%Nano-cellulose prepared by sol-gel method was characterized by using Fourier transform infrared(FTIR) spectroscopy,X-ray diffraction(XRD),thermal gravimetric analysis(TGA),transmission electron microscopy(TEM) and laser particle size test.The results showed that supramolecular structure of microcrystalline cellulose(MCC) as raw material was cellulose I,while the prepared nano-cellulose was cellulose Ⅱ.The crystallinity of MCC was calculated as 87.54 %,for nano-cellulose,the crystallinity was 73.49 %.The crystallinity of nano-cellulose decreased slightly compared with that of MCC.The thermal stability of nano-cellulose was less than that of MCC.The mean size of nano-cellulose was 425 nm,its particle size distribution appeared normal distribution.Aspect ratio of nano-cellulose was 5∶1 to 40∶1.

  8. Photodegradation of Azo-dye by Y2O3/TiO2 Loaded on Carboxymethyl Cellulose Films

    Institute of Scientific and Technical Information of China (English)

    HE Xiao-yun; CHEN Ri-yao; ZHENG Xi; CHEN Zhen

    2005-01-01

    Nanosize TiO2, Y2 O3/TiO2 particles were prepared by the sol-gel process. The structure was characterized by means of XRD,TEM. The photoelectric properties of the nanoparticles were studied by PL.The thickness and the surface of the carboxymethyl cellulose film was measured by SEM. Based on a model reaction, the photocatalytic degradation of methylene blue with positive charge was investigated in TiO2,Y2O3/TiO2 nanopowder composite films irradiated by UV lamp. The results revealed that the degradation process belonged to the first-order kinetic reaction.

  9. Tribo-electric charging and adhesion of cellulose ethers and their mixtures with flurbiprofen.

    Science.gov (United States)

    Ghori, Muhammad U; Supuk, Enes; Conway, Barbara R

    2014-12-18

    The pervasiveness of tribo-electric charge during pharmaceutical processing can lead to the exacerbation of a range of problems including segregation, content heterogeneity and particle surface adhesion. The excipients, hydroxypropyl methylcellulose (HPMC) and methylcellulose (MC), are often used in drug delivery systems and so it is important to understand the impact of associated factors on their charging and adhesion mechanisms, however, little work has been reported in this area. Such phenomena become more prominent when excipients are introduced to a powder mixture alongside the active pharmaceutical ingredient(s) (APIs) with inter- and intra-particulate interactions giving rise to electrification and surface adhesion of powder particles. The aim of this study was to understand the impact of material attributes (particle size, hydroxypropyl (Hpo) to methoxyl (Meo) ratio and molecular size) on the charging and adhesion characteristics of cellulose ethers. Furthermore, a poorly compactible and highly electrostatically charged drug, flurbiprofen, was used to develop binary powder mixtures having different polymer to drug ratios and the relationship between tribo-electric charging and surface adhesion was studied. Charge was induced on powder particles and measured using a custom built device based on a shaking concept, consisting of a Faraday cup connected to an electrometer. The diversity in physicochemical properties has shown a significant impact on the tribo-electric charging and adhesion behaviour of MC and HPMC. Moreover, the adhesion and electrostatic charge of the API was significantly reduced when MC and HPMC were incorporated and tribo-electric charging showed a linear relationship (R(2)=0.81-0.98) with particle surface adhesion, however, other factors were also involved. It is anticipated that such a reduction in charge and particle surface adhesion would improve flow and compaction properties during processing.

  10. Physicochemical properties and mechanism of drug release from ethyl cellulose matrix tablets prepared by direct compression and hot-melt extrusion.

    Science.gov (United States)

    Crowley, Michael M; Schroeder, Britta; Fredersdorf, Anke; Obara, Sakae; Talarico, Mark; Kucera, Shawn; McGinity, James W

    2004-01-28

    The objective of this research project was to determine the physicochemical properties and investigate the drug release mechanism from ethyl cellulose (EC) matrix tablets prepared by either direct compression or hot-melt extrusion (HME) of binary mixtures of water soluble drug (guaifenesin) and the polymer. Ethyl cellulose was separated into "fine" or "coarse" particle size fractions corresponding to 325-80 and 80-30 mesh particles, respectively. Tablets containing 30% guaifenesin were prepared at 10, 30, or 50 kN compaction forces and extruded at processing temperatures of 80-90 and 90-110 degrees C. The drug dissolution and release kinetics were determined and the tablet pore characteristics, tortuosity, thermal properties and surface morphologies were studied using helium pycnometry, mercury porosimetry, differential scanning calorimetry and scanning electron microscopy. The tortuosity was measured directly by a novel technique that allows for the calculation of diffusion coefficients in three experiments. The Higuchi diffusion model, Percolation Theory and Polymer Free Volume Theory were applied to the dissolution data to explain the release properties of drug from the matrix systems. The release rate was shown to be dependent on the ethyl cellulose particle size, compaction force and extrusion temperature.

  11. Dissolution and bioavailability of lercanidipine-hydroxypropylmethyl cellulose nanoparticles with surfactant.

    Science.gov (United States)

    Ha, Eun-Sol; Choo, Gwang-Ho; Baek, In-hwan; Kim, Jung-Soo; Cho, Wonkyung; Jung, Young Suk; Jin, Su-Eon; Hwang, Sung-Joo; Kim, Min-Soo

    2015-01-01

    The objective of this study was to develop lercanidipine-hydroxypropylmethyl cellulose (HPMC) nanoparticles with high oral bioavailability. The lercanidipine-HPMC nanoparticles with/without surfactants were manufactured using a supercritical antisolvent (SAS) process. Gelucire 44/14, poloxamer 407, and d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) were evaluated as surfactants. Spherical lercanidipine-HPMC nanoparticles with a mean particle size less than 400 nm were successfully prepared using a SAS process. The dissolution and oral bioavailability of lercanidipine was significantly increased by addition of surfactants. Especially lercanidipine-HPMC nanoparticles with TPGS showed a 2.47-fold higher oral bioavailability than raw material. Furthermore, the dissolution efficiency was strongly correlated to the in vivo Cmax and AUC0 → 24h. Therefore, the preparation of HPMC nanoparticles with TPGS using a SAS process is a highly effective formulation strategy for enhanced oral bioavailability of lercanidipine.

  12. Paramagnetic Cellulose DNA Isolation Improves DNA Yield and Quality Among Diverse Plant Taxa

    Directory of Open Access Journals (Sweden)

    Jackson R. Moeller

    2014-10-01

    Full Text Available Premise of the study: The chemical diversity of land plants ensures that no single DNA isolation method results in high yield and purity with little effort for all species. Here we evaluate a new technique originally developed for forensic science, based on MagnaCel paramagnetic cellulose particles (PMC, to determine its efficacy in extracting DNA from 25 plant species representing 21 families and 15 orders. Methods and Results: Yield and purity of DNA isolated by PMC, DNeasy Plant Mini Kit (silica column, and cetyltrimethylammonium bromide (CTAB methods were compared among four individuals for each of 25 plant species. PMC gave a two-fold advantage in average yield, and the relative advantage of the PMC method was greatest for samples with the lowest DNA yields. PMC also produced more consistent sample purity based on absorbance ratios at 260 : 280 and 260 : 230 nm. Conclusions: PMC technology is a promising alternative for plant DNA isolation.

  13. Particle physics

    CERN Document Server

    Martin, Brian R

    2017-01-01

    An accessible and carefully structured introduction to Particle Physics, including important coverage of the Higgs Boson and recent progress in neutrino physics. Fourth edition of this successful title in the Manchester Physics series. Includes information on recent key discoveries including : An account of the discovery of exotic hadrons, beyond the simple quark model; Expanded treatments of neutrino physics and CP violation in B-decays; An updated account of ‘physics beyond the standard model’, including the interaction of particle physics with cosmology; Additional problems in all chapters, with solutions to selected problems available on the book’s website; Advanced material appears in optional starred sections.

  14. Absorbent properties of carboxymethylated fiber, hydroentangled nonwoven and regenerated cellulose: a comparative study

    Science.gov (United States)

    Commercially-available, bleached cotton fibers, rayon, and their hydroentangled counterparts were carboxymethylated to produce cellulosic products with increased absorbency. These cellulose materials were tested for absorbance, spectroscopic properties, degree of substitution and carding ability. Ca...

  15. Development of green nanocomposites reinforced by cellulose nanofibers extracted from paper sludge

    Science.gov (United States)

    Takagi, Hitoshi; Nakagaito, Antonio N.; Kusaka, Kazuya; Muneta, Yuya

    2015-03-01

    Cellulose nanofibers have been showing much greater potential to enhance the mechanical and physical properties of polymer-based composite materials. The purpose of this study is to extract the cellulose nanofibers from waste bio-resources; such as waste newspaper and paper sludge. The cellulosic raw materials were treated chemically and physically in order to extract individualized cellulose nanofiber. The combination of acid hydrolysis and following mechanical treatment resulted in the extraction of cellulose nanofibers having diameter of about 40 nm. In order to examine the reinforcing effect of the extracted cellulose nanofibers, fully biodegradable green nanocomposites were fabricated by composing polyvinyl alcohol (PVA) resin with the extracted cellulose nanofibers, and then the tensile tests were conducted. The results showed that the enhancement in mechanical properties was successfully obtained in the cellulose nanofiber/PVA green nanocomposites.

  16. Effects of ionic catalysis on hydrogen production by the steam gasification of cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Su, Shen [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Li, Wen; Bai, Zongqing; Bai, Jin [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Xiang, Hongwei [Graduate University of Chinese Academy of Sciences, Beijing 100039 (China)

    2010-05-15

    In this study, significant effects of ionic catalysis on the formation of H{sub 2} and CO during the steam gasification process of cellulose are revealed. The energy of the C-H bonds of cellulose can be remarkably reduced by Na{sup +} and OH{sup -} ions produced by the dissociation of NaOH, enabling dehydrogenation of cellulose at low temperature. Dehydrogenation of cellulose is evidently affected by the concentration of Na{sup +} and OH{sup -} ions that cellulose can come into contact with. Higher concentrations of Na{sup +} and OH{sup -} ions can reduce the initial dehydrogenation temperature of cellulose to lower than 403 K. The production of CO increases after this remarkable dehydrogenation of cellulose, which indicates that the C-O bonds of cellulose are prone to forming CO by pyrolysis. (author)

  17. 75 FR 42745 - Production Incentives for Cellulosic Biofuels: Notice of Program Intent

    Science.gov (United States)

    2010-07-22

    ... of Energy Efficiency and Renewable Energy Production Incentives for Cellulosic Biofuels: Notice of..., biofuels producers and other interested parties are invited to submit pre-auction eligibility information..., ``Production Incentives for Cellulosic Biofuels; Reverse Auction Procedures and Standards,'' (74 FR...

  18. Characterization of the crystalline structure of cellulose using static and dynamic FT-IR spectroscopy.

    Science.gov (United States)

    Akerholm, Margaretha; Hinterstoisser, Barbara; Salmén, Lennart

    2004-02-25

    The cellulose structure is a factor of major importance for the strength properties of wood pulp fibers. The ability to characterize small differences in the crystalline structures of cellulose from fibers of different origins is thus highly important. In this work, dynamic FT-IR spectroscopy has been further explored as a method sensitive to cellulose structure variations. Using a model system of two different celluloses, the relation between spectral information and the relative cellulose Ialpha content was investigated. This relation was then used to determine the relative cellulose Ialpha content in different pulps. The estimated cellulose I allomorph compositions were found to be reasonable for both unbleached and bleached chemical pulps. In addition, it was found that the dynamic FT-IR spectroscopy technique had the potential to indicate possible correlation field splitting peaks of cellulose Ibeta.

  19. Cellulose fibers extracted from rice and oat husks and their application in hydrogel.

    Science.gov (United States)

    Oliveira, Jean Paulo de; Bruni, Graziella Pinheiro; Lima, Karina Oliveira; Halal, Shanise Lisie Mello El; Rosa, Gabriela Silveira da; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-04-15

    The commercial cellulose fibers and cellulose fibers extracted from rice and oat husks were analyzed by chemical composition, morphology, functional groups, crystallinity and thermal properties. The cellulose fibers from rice and oat husks were used to produce hydrogels with poly (vinyl alcohol). The fibers presented different structural, crystallinity, and thermal properties, depending on the cellulose source. The hydrogel from rice cellulose fibers had a network structure with a similar agglomeration sponge, with more homogeneous pores compared to the hydrogel from oat cellulose fibers. The hydrogels prepared from the cellulose extracted from rice and oat husks showed water absorption capacity of 141.6-392.1% and high opacity. The highest water absorption capacity and maximum stress the compression were presented by rice cellulose hydrogel at 25°C. These results show that the use of agro-industrial residues is promising for the biomaterial field, especially in the preparation of hydrogels.

  20. Peptide-cellulose conjugates for protease point of care diagnostics and treatment

    Science.gov (United States)

    Peptide-cellulose conjugates containing Human Neutrophil Elastase substrate sequences with both colorimetric and fluorometric signal molecules have been synthesized on a variety of cellulosic and nanocellulosic substrates including cotton and wood nanocrystals, wood nanocomposites, cotton-based aero...